When SDLT comes back: the three routes and three clocks

When a buyer has paid Stamp Duty Land Tax (SDLT) they did not ultimately owe, the money is recoverable, but only inside the right window and via the right route. The trap for conveyancers is that there are three different routes, and they run on three different clocks. Choose the wrong route, or assume the wrong clock, and a recoverable overpayment can become an irrecoverable loss.

First, the jurisdiction. SDLT applies in England and Northern Ireland only, and is administered by HMRC. Scotland uses Land and Buildings Transaction Tax (LBTT) through Revenue Scotland, and Wales uses Land Transaction Tax (LTT) through the Welsh Revenue Authority, each with its own refund rules and time limits. This guide is about SDLT; the devolved equivalents are flagged at the end.

The three SDLT routes are:

  • The higher-rate surcharge refund, where the buyer paid the additional-dwelling surcharge but has now sold their previous main residence: claimed by the later of 12 months from selling the old home or 12 months from the SDLT return's filing date, with the old home sold within 3 years.
  • Amending the return, where the return itself contained an error: within 12 months of the filing date.
  • Overpayment relief, the catch-all once the amendment window has closed: up to 4 years from the effective date of the transaction.

The deadline depends on which route applies, so the first job on any potential refund is to identify the route correctly.

The higher-rate surcharge: why a refund arises

The higher rates for additional dwellings (HRAD) surcharge is 5% for transactions with an effective date on or after 31 October 2024 (raised from 3%; contracts exchanged on or before 30 October 2024 keep the 3% rate). It applies on top of the standard residential rates where, on the day of the transaction, the buyer owns more than one dwelling.

A buyer who completes the purchase of a new main home before they have sold their old one therefore pays the surcharge up front, because on the day of completion they own two dwellings. When they later sell the old main residence, the transaction is recharacterised as a replacement of their only or main residence rather than the acquisition of an additional dwelling, and the surcharge they paid becomes refundable. The refund is the difference between what they paid (with the surcharge) and what was actually due (without it). This pattern, surcharge paid because the old home had not yet sold, then refundable once it does, is by far the most common SDLT refund a conveyancer handles.

The surcharge can be substantial, because it is a flat percentage applied to the whole consideration on top of the standard bands rather than a small slice. On a meaningful purchase price, the 5% surcharge alone can run to a large sum, which is precisely why the refund matters to the client and why a missed window is such a costly oversight. It is also why the surcharge refund, rather than the smaller corrections handled by amendment, is the route conveyancers most need a reliable system for.

The refund deadline: the LATER of two dates

This is the section that is most often got wrong, so it is worth stating precisely. For the higher-rate surcharge refund, HMRC must receive the refund request by whichever date is the later of:

  • 12 months after the date of sale of the previous main home, or
  • 12 months after the filing date of the SDLT return for the new purchase.

The word that carries the weight is "later". A great deal of consumer and adviser content says only "within 12 months" without specifying which 12 months, which is how clients miss the deadline. For a buyer who completes the new purchase and then sells the old home several months later, the 12-months-from-sale date will fall after the 12-months-from-filing date, so the clock runs from the sale of the old home. The filing date is 14 days after the effective date of the new purchase.

Alongside the claim deadline sits a separate eligibility condition: the previous main home must have been sold within 3 years (36 months) of buying the new property, unless exceptional circumstances apply. These are two distinct tests. You need both the old home sold within 3 years and the refund claimed within the later-of window. Treat the 3-year sale rule as the working deadline for the sale itself, and the later-of rule as the deadline for the claim.

The reason the distinction matters is that the two clocks can produce very different end dates. Suppose the new purchase completes and the SDLT return is filed promptly, but the old home does not sell for two and a half years. The 12-months-from-filing date will have passed long ago, yet the claim is still in time because the 12-months-from-sale date is later and is the one that governs. Conversely, if the old home is sold very quickly, within a few weeks of the new purchase, the 12-months-from-filing date may be the later of the two, so the claim clock effectively tracks the filing date. The safe practice is to calculate both dates on every replacement case and diarise the later one, rather than assume which clock applies.

It is worth stressing what the 3-year rule is not. It is not the claim deadline. A buyer who sells the old home in, say, month 30 has satisfied the 3-year sale test, but the claim must still be made within 12 months of that sale (or 12 months of the filing date, if later). Treating the 36-month sale window as if it were the deadline for the refund claim itself is one of the more common and damaging mistakes in this area, because it can lead a firm to believe a claim is still live when in fact the 12-month claim clock has already run.

How the firm makes the higher-rate refund claim

The claim can be made by the purchaser or by an agent acting on their behalf, so the conveyancing firm can submit it for the client. The process, kept at a practical level:

  1. Confirm eligibility. The new property is the client's only or main residence (a genuine replacement), and both the 3-year sale test and the refund-claim window are met.
  2. Gather the details. The completion dates for both the purchase and the sale of the old home, and the unique transaction reference number (UTRN) of the original SDLT return.
  3. Submit the repayment request to HMRC, online or by post, calculating the surcharge element being reclaimed.
  4. Diarise the deadline. Record the later-of date as a hard diary entry so the claim is never lost to oversight.

This is process, not a step-by-step walkthrough of an HMRC form, which can change. The discipline that matters is identifying the case early and diarising the clock.

Amending an SDLT return (the 12-month route)

Where the original return contained an error, the route is to amend the return. You have 12 months from the filing date to amend (the filing date being 14 days after the effective date). Use amendment where the return was wrong on its own terms: the wrong rate band was applied, a relief was missed or wrongly claimed, or the bands were miscalculated.

The key distinction from the surcharge refund is that amendment corrects the return itself, because the return was wrong, whereas the surcharge refund leaves the original return intact (it was correct on the day, when the buyer owned two dwellings) and reclaims the surcharge on the basis of a later event (the sale of the old home). If you are inside 12 months of the filing date and the return contained an error, amendment is the cleaner route.

Because the amendment window is measured from the filing date, and the filing date is only 14 days after the effective date, the practical effect is that you have a little over a year from completion to spot and fix an error on the return. That is a relatively short runway. Errors of the kind that drive amendments (a relief missed, the wrong band applied, a miscalculation) are most easily caught at or shortly after submission, while the file is fresh, which is another argument for a post-completion check of every SDLT return rather than relying on the error surfacing later.

Overpayment relief (the 4-year route)

If it has been more than a year since the filing date of the SDLT return, but no more than 4 years since the effective date of the transaction, you can make a claim for overpayment relief. This is the catch-all for SDLT that was paid but not due, once the 12-month amendment window has closed.

Overpayment relief carries its own conditions and is more demanding than a simple amendment, so it is the route of last resort. The practical lesson is to identify overpayments early: while you are still inside 12 months of the filing date, amendment is simpler; once that window passes, you are pushed onto overpayment relief and its 4-year longstop from the effective date. After 4 years from the effective date, the position is generally closed.

Note also that overpayment relief and the surcharge refund are different things and should not be confused. The surcharge refund is a specific statutory route for the replacement-of-main-residence case, with its own later-of deadline; overpayment relief is the general route for SDLT paid that was not due, used where no more specific route is open and the amendment window has gone. A replacement-of-main-residence buyer who is inside the surcharge-refund window should use that route, not overpayment relief. Mapping the facts to the correct route first, and only then reading off the clock, is what keeps these claims clean.

Common SDLT overpayment scenarios conveyancers see

A handful of fact patterns recur. Each one maps to a route and a clock:

  • Surcharge paid, then old home sold. Route 1, the higher-rate surcharge refund (later of 12 months from sale or filing date; old home sold within 3 years).
  • First-time-buyer relief or a multiple-dwellings or mixed-use position missed on the original return. Amend within 12 months of the filing date, or claim overpayment relief if that window has closed.
  • The wrong nil-rate band used on a return straddling 1 April 2025. The temporary £250,000 nil-rate band and the £425,000 and £625,000 first-time-buyer thresholds ended on 31 March 2025; from 1 April 2025 the nil-rate band is £125,000 and first-time-buyer relief runs to £300,000. A return that used the old figures for a post-1-April-2025 transaction is an error: amend, or claim overpayment relief.
  • The non-resident 2% surcharge applied where the buyer in fact met the residence test. An error on the return: amend or claim overpayment relief depending on timing.

For the underlying rates and how the bands are applied, see our guide on SDLT calculation for UK conveyancing solicitors.

The firm's role, fee and VAT

Two VAT points keep the firm's own position clean. First, the SDLT you paid for the client at completion was a disbursement: you acted as a conduit for a tax the client was liable for, so it carried no VAT on the recharge to the client. Second, the work you do to advise on and make the refund or overpayment claim is a fresh supply of legal and advisory services, which is standard-rated for VAT at 20%. So you charge VAT on your fee for the claim work; the refunded SDLT itself is the client's money and carries no VAT.

It is worth being precise about how the refund flows through the firm's books. The repaid SDLT is the client's money: when it is received it should be handled like any other client receipt and accounted to the client, not treated as the firm's income. The firm's fee for the claim work is separate, is invoiced to the client, and carries output VAT at 20%. Keeping these two streams distinct (client money in, firm fee plus VAT out) avoids both a VAT error on the fee and any suggestion that the refund itself was the firm's to keep.

A word of caution on the market. HMRC has flagged concerns about cold-call SDLT reclaim companies that take a contingent cut and file weak or speculative claims, which can leave the buyer exposed if HMRC later challenges the refund. The conveyancing firm that handled the purchase already holds the file and the facts and is well placed to make a properly evidenced claim, which is generally the safer route for the client. For the VAT framework across conveyancing, see our guide on conveyancing VAT rules for 2025/26.

Devolved equivalents: LBTT and LTT refunds

The SDLT windows do not apply in Scotland or Wales. Scotland's LBTT Additional Dwelling Supplement (ADS), which is 8% for contracts entered into on or after 5 December 2024, has its own repayment route and time limits through Revenue Scotland. Wales's LTT, which uses higher residential rate tables (the opening higher rate rose to 5% from 11 December 2024) rather than a flat surcharge, has its higher-rates refund route through the Welsh Revenue Authority.

Do not import the SDLT later-of rule, the 12-month amendment window or the 4-year overpayment-relief longstop into an LBTT or LTT matter; check the relevant devolved authority's own rules and clocks. For the Scottish and Welsh positions, see our guides on LBTT rates for Scottish conveyancing firms and LTT versus SDLT for Welsh conveyancing.

Negligence and diary risk for the firm

A missed refund window is not just the client's problem. If a recoverable surcharge refund is lost because the deadline was reached without a claim, that can crystallise a client loss and a professional indemnity claim against the firm. The exposure is straightforward to manage: a system that flags replacement-of-main-residence cases at the point of instruction, and diarises the surcharge-refund deadline (the later-of date) as a hard entry, removes the risk of losing a claim to oversight.

This should be proportionate rather than alarmist. The point is simply that the refund windows are a known, recurring risk that a small piece of process eliminates. For the related risk management, see our guide on the tax treatment of professional indemnity insurance.

Worked examples

These are illustrative sketches to show how the routes and clocks work, not advice on any particular matter.

Example 1: surcharge refund, the "later of" deadline

A buyer completes a new main home in England in January while still owning their old home, paying the 5% HRAD surcharge because, on the day, they own two dwellings. They sell the old home 14 months later. The refund deadline is the later of (a) 12 months after that sale or (b) 12 months after the new purchase's SDLT filing date. Here (a) is later, so the clock runs from the sale of the old home. Both the 3-year sale test and the refund window are met, and the surcharge is recoverable. The lesson: the refund clock is the later of two dates; here it runs from the sale of the old home.

Example 2: wrong band on a straddle return, amend within 12 months

A return filed in April 2025 mistakenly used the temporary £250,000 nil-rate band that ended on 31 March 2025, overstating the relief and (in this case) producing a different figure from the correct £125,000 band. Spotted within the year, the firm amends the return within 12 months of the filing date and recovers the overpayment. The lesson: an error on the face of the return is an amendment, not an overpayment-relief claim, if you are inside 12 months of the filing date.

Example 3: closed amendment window, overpayment relief

A relief that should have been claimed was missed, and the error is discovered 2 years after completion. The 12-month amendment window has closed, but the firm is still within 4 years of the effective date, so it claims overpayment relief instead. The lesson: after 12 months, the route is overpayment relief, available up to 4 years from the effective date.

Where firms get this wrong, and how a specialist helps

The recurring failures are about routes and clocks: citing "within 12 months" for the surcharge refund without specifying the later of the two dates; conflating the claim deadline with the 3-year sale rule; reaching for overpayment relief when amendment was still available; and, worst of all, letting a refund window pass unflagged. Each is avoidable with a clear taxonomy of the three routes and a diary discipline tied to the filing date and the sale of the old home.

Sibling topics in this cluster cover the related conveyancing edge cases: non-resident and corporate-buyer SDLT for conveyancers and abortive conveyancing transactions, VAT and WIP.

If you run a conveyancing practice and want the way your firm identifies, routes and diarises SDLT refunds reviewed by accountants who work only with law firms, we can help you build a system that protects both your clients and the firm. Getting the route and the clock right every time is a small process change that removes a recurring negligence risk and keeps the refund work properly billed and VAT-accounted.