Amending an SDLT return and claiming a higher-rate refund: the UK process for 2026

Stamp Duty Land Tax (SDLT) returns are filed quickly — but the rules for fixing them, and for reclaiming the 5% higher-rate surcharge after you sell your previous main residence, run on slower clocks. This guide walks through the two procedures HMRC actually publishes: how to amend an SDLT return after filing, and how the dedicated higher-rates refund service works.

Across the 913,255 residential transactions in England and Wales above the £40,000 surcharge threshold in 2024 (HM Land Registry, fetched 2026-05-17 from truecost.db), a meaningful slice involve buyers who either need to correct the original return or who pay the additional-dwelling surcharge upfront and then claim it back when they sell their previous main residence. The procedures are different and the deadlines do not overlap cleanly — getting them confused is the most common reason refunds and corrections fail.

How the 14-day filing window works

Since 1 March 2019, SDLT returns must be filed and any tax paid within 14 days of the "effective date" of the transaction — usually the completion date (HMRC: Stamp Duty Land Tax — when you must file your return). Before March 2019 the window was 30 days. Almost all returns are filed by the buyer's conveyancer through HMRC's SDLT online service, which issues a Unique Transaction Reference Number (UTRN) on submission. That UTRN is the single identifier you need for every later correction, amendment or refund claim.

Why returns get amended

Common, documented reasons for amending an SDLT return after filing:

The first three categories are typically handled as an amendment to the return; the higher-rate surcharge reclaim has its own dedicated route, covered below.

Amending within 12 months of filing

The standard amendment window for an SDLT return runs for 12 months from the filing date (Schedule 10, paragraph 6, Finance Act 2003). Within that window the amendment is made through HMRC's SDLT online amendment service, quoting the UTRN. Most conveyancers will file it on the buyer's behalf — if the original transaction was handled by a solicitor, they hold the UTRN and the agent credentials.

HMRC also has its own enquiry window: it can open an enquiry into an SDLT return up to 9 months after the filing date (Sch 10, para 12 FA 2003). During an open enquiry the buyer cannot make an amendment that affects the matter under enquiry until the enquiry closes.

After 12 months — the overpayment relief route

Once the 12-month amendment window has closed, an SDLT return cannot be amended in the normal sense. Instead, a claim for overpayment relief under Schedule 10, paragraph 34 of the Finance Act 2003 can be made within four years of the effective date of the transaction. This claim is made in writing — there is no online service — to:

BT Stamp Duty Land Tax

HM Revenue and Customs

BX9 1HD

The letter must state the grounds for the claim, attach evidence (completion statement, contract, FTB declaration, etc.), and quote the UTRN. Overpayment relief is narrower than the amendment route: there are statutory exclusions (for example, a mistake of law that has since been corrected by case law cannot always be relied on). HMRC's SDLT manual section SDLTM54100 sets out the bars.

The higher-rate surcharge refund: a separate procedure

When a buyer owns an existing main residence and completes on a new main residence before selling the old one, they must pay the 5% higher-rate SDLT surcharge on the new purchase (the rate moved from 3% to 5% on 31 October 2024 under the Autumn Budget 2024 measure; see HMRC: Higher rates of Stamp Duty Land Tax).

If the previous main residence is then sold within 36 months of the new purchase, the buyer can reclaim that surcharge. This is not an amendment to the original SDLT return; it is a refund claim filed through a dedicated gov.uk online service: Apply for a repayment of the higher rates of Stamp Duty Land Tax for additional properties.

The claim must be made within 12 months of either:

• the completion date of the sale of the previous main residence, or
• the filing date of the SDLT return for the new home,

whichever is later (HMRC SDLT manual, SDLTM09807). The 36-month replacement window and the 12-month claim window run on different clocks: missing the 12-month claim window is the single most common procedural failure cited in our companion piece on why higher-rate refund claims are refused.

Evidence the refund service asks for

According to the gov.uk service guidance:

• UTRN of the original SDLT return on the new property
• Completion date of the new (replacement) main residence
• Completion date of the sale of the previous main residence
• Address of both properties
• Buyer's name, date of birth, NI number, and bank details for the refund
• Where the claim is made by an agent, an authority letter signed by the buyer

The service returns the surcharge element of the original SDLT — the standard SDLT bill on the new property is unchanged.

Worked example: £300,000 replacement-of-main-residence refund

A buyer completes on a new £300,000 main residence on 1 June 2026 while still owning their previous main residence. Standard SDLT on £300,000 in England (2026 rates: 0% to £125,000; 2% on the £125,001–£250,000 slice; 5% on the £250,001–£925,000 slice) is £5,000. The 5% higher-rate surcharge applies to the full purchase price: £15,000. Total at completion: £20,000, filed within 14 days.

If the old main residence is sold on 1 December 2027 (18 months later, within the 36-month window), the buyer can claim back the £15,000 surcharge. The claim must reach HMRC by 1 December 2028 at the latest — 12 months after the disposal. The standard £5,000 stays paid.

Try the Homecost cost-of-buying tool to see a stamp duty breakdown for any UK postcode, including the higher-rate surcharge where applicable.

Common timing traps

1. Counting the 36 months from the wrong date. It runs from the completion date of the new purchase, not the date the buyer moved in or the date contracts were exchanged.
2. Missing the 12-month claim deadline. Sellers who took longer than expected to dispose of the old home sometimes assume they have plenty of time once it eventually completes — they do, but only 12 months.
3. Believing an amendment refund and a higher-rate refund are the same thing. They are not. An amendment corrects facts on the original return; the higher-rate refund is a separate claim under Sch 4ZA FA 2003.
4. Filing the higher-rate refund before the old property has sold. HMRC's service requires the disposal to have completed before the claim is made.
5. Forgetting about devolved regimes. Properties in Scotland and Wales use LBTT and LTT, not SDLT, and both have their own surcharge-refund mechanics through Revenue Scotland and the Welsh Revenue Authority — neither is filed through the gov.uk SDLT refund service.

What this is — and isn't

This guide explains how the published HMRC processes work, drawing on the gov.uk service pages, the SDLT manual and the underlying Finance Act 2003 provisions. It is general information, not advice on whether to file or what evidence to attach in any specific case. The same purchase facts can produce different SDLT outcomes depending on questions HMRC has not always resolved publicly (annex configuration, what counts as "main residence" status at a point in time, the meaning of "majority interest" in joint purchases).

Speak to a qualified solicitor or chartered tax adviser before submitting an amendment or refund claim — particularly where the surcharge sum is significant or the transaction involves trusts, companies, divorce settlements or estates. For background on the 5% surcharge mechanics that generates most of these refund claims, see our explainer on the additional-property stamp duty surcharge, and for the wider stamp-duty cluster see /blog?category=cost-intelligence.

Based on 921,873 Land Registry residential transactions in 2024 and HMRC's published SDLT manual sections SDLTM09807, SDLTM09812 and SDLTM54100.