SDLT Refund: How to Claim Back Overpaid Stamp Duty — and the Most Common Overpayments

Why SDLT Overpayments Are Common

Stamp Duty Land Tax is administered through self-assessment — the buyer (via their conveyancer) calculates the SDLT due and submits an SDLT1 return to HMRC within 14 days of completion. Unlike income tax, where HMRC calculates the liability, SDLT calculation is entirely the buyer's responsibility.

SDLT legislation is notoriously complex. The Finance Act 2003 (which introduced SDLT) and its subsequent amendments run to hundreds of pages. Reliefs and exemptions are numerous, nuanced and frequently interact with each other in non-obvious ways. Conveyancers, particularly those not specialising in tax, can and do miss reliefs that would have reduced the charge. The result is a significant volume of overpaid SDLT that can be reclaimed.

The Time Limit for Claiming Overpaid SDLT

SDLT returns can be amended within 12 months of the filing date (i.e. within 12 months of the filing deadline of 14 days post-completion). For transactions that completed in 2025, the amendment window closes in early 2026.

After the 12-month amendment window, the only route to a refund is an overpayment relief claim under Schedule 11A to the Finance Act 2003. This can be made within four years of the effective date of the transaction. For transactions completing in 2022, the four-year window closes in 2026.

Both routes require the buyer (or their representative) to submit a formal claim to HMRC. Claims made by SDLT reclaim specialists on a "no win, no fee" basis have proliferated since the introduction of the higher rate surcharge in 2016, though HMRC has challenged some of the more aggressive reclaim strategies in the First-tier Tax Tribunal.

The Most Common SDLT Overpayments

**1. The 3% Higher Rate Surcharge — Replacement of Main Residence**

A 3% SDLT surcharge applies to purchases of additional residential properties (buy-to-let, second homes) under Schedule 4ZA to the Finance Act 2003. However, if the buyer sells their previous main residence within three years of buying the new property, they can claim a refund of the surcharge.

This "replacement of main residence" refund is the most common SDLT reclaim. It applies where, at the time of purchasing the new property, the buyer had not yet sold their existing main residence (perhaps because the chain had not completed) and therefore paid the 3% surcharge, but subsequently completed the sale of the old home.

The refund must be claimed within 12 months of selling the previous main residence, or within 12 months of the filing date of the SDLT return, whichever is later.

**2. Multiple Dwellings Relief (MDR)**

Where a transaction involves the acquisition of more than one dwelling in a single transaction (or linked transactions), Multiple Dwellings Relief under section 58D of and Schedule 6B to the Finance Act 2003 may be available. MDR calculates SDLT by reference to the average dwelling price rather than the total transaction price, which often produces a lower charge.

Note: MDR was abolished for transactions completing on or after 1 June 2024, following HMRC's consultation and announcement in the Autumn Statement 2023. For transactions that completed before that date, MDR claims remain available within the relevant time limits.

**3. Mixed-Use Property Misclassification**

SDLT on mixed-use (part-residential, part-commercial) property is calculated using non-residential rates, which are significantly lower than residential rates for many price points. A property misclassified as entirely residential when it has a commercial element (an outbuilding used for a trade, a room used as a professional consulting room, land used for grazing or commercial purposes) may have attracted an overpayment.

The boundary between residential and mixed-use classification has been heavily litigated in the Tax Tribunal and there is extensive case law. Cases including Hyman v HMRC [2021] UKUT 0068 and P N Bewley Ltd v HMRC [2019] have clarified and in some cases narrowed the scope for mixed-use claims.

**4. Uninhabitable Properties**

The residential rates of SDLT (including the higher rate surcharge) do not apply where a property is not suitable for use as a dwelling at the date of completion. Properties that are derelict, structurally unsound, or otherwise uninhabitable at completion may be eligible for the non-residential rate.

HMRC's position on this relief has evolved following the Tax Tribunal decisions in Bewley and others. The relief is genuine but requires contemporaneous evidence (photographs, surveys, structural reports) confirming the property's condition at the date of completion.

**5. First-Time Buyer Relief Miscalculation**

First-time buyer relief under Schedule 6ZA to the Finance Act 2003 provides reduced SDLT rates for first-time buyers purchasing properties up to £625,000. Where a buyer's conveyancer incorrectly assessed eligibility or applied the wrong rates, a refund may be available.

How to Claim

Refunds within the 12-month amendment window: ask your original conveyancer to submit an amendment to the SDLT1 return, or appoint a specialist to do so.

Refunds via overpayment relief (up to four years): complete and submit form SDLT7 (overpayment relief claim) to HMRC Stamp Taxes. Include full details of the original transaction, the basis of the overpayment, and the amount claimed. HMRC will investigate the claim and either make payment or issue a decision notice explaining why the claim is refused. Disputed claims can be appealed to the First-tier Tax Tribunal.