How do you correct an SDLT overpayment when HMRC wants a completion statement?

Introduction

People often search for this issue after discovering that the wrong amount of Stamp Duty Land Tax (SDLT) was paid on a property purchase. In many cases, the error only comes to light after the SDLT return has already been filed and HMRC has written to the buyer or their adviser. A common practical problem is that HMRC asks for documentary evidence, especially the completion statement, before it will consider amending the position or repaying any overpaid tax.

Where the mistake arose from a conveyancing or administrative error, the key question is usually not whether the position can be corrected, but whether the taxpayer has enough evidence to satisfy HMRC. The completion statement is often central to that process.

The Question

A buyer was told that an SDLT calculation used on completion was wrong because of an error made during the conveyancing process. HMRC had already sent correspondence before the mistake was corrected. The revised position suggested that the buyer had overpaid SDLT and that the correct tax figure should have been lower, creating a potential refund.

The difficulty was that, although there was email correspondence from the conveyancer showing the corrected position, the buyer did not yet have an updated completion statement. HMRC had specifically asked for a completion statement for the transaction. The issue was whether the refund claim could proceed and what evidence was needed.

Nick’s Explanation

Nick’s explanation was straightforward. He identified that the SDLT assessment originally used for the transaction was inaccurate because of a clerical error in the conveyancing process. He also noted that HMRC’s earlier letter had arrived before that mistake had been corrected.

His practical view was that the matter could still be put back to HMRC using the correct refund figure, but that the supporting evidence mattered. In anonymised form, his point was this: HMRC had asked for a completion statement, and while email confirmation from the conveyancer might help, HMRC could refuse the refund if the evidence was not sufficiently formal or complete.

In substance, Nick’s advice was that the buyer should obtain an updated completion statement showing the correct SDLT amount and submit that to HMRC with the revised figures. That is sensible advice, because HMRC commonly expects transaction-level evidence rather than informal correspondence alone.

The Law

SDLT is charged under the Finance Act 2003. The amount due depends on the effective date of the transaction, the chargeable consideration, the nature of the property, and whether any higher rates or reliefs apply.

In broad terms, the relevant legal framework includes:

• the requirement to file an SDLT return and pay the tax due;
• the ability to amend a return within the statutory amendment window, where that window is still open;
• the possibility of claiming repayment where too much tax has been paid, subject to the relevant statutory route and time limits; and
• HMRC’s power to request evidence supporting the taxpayer’s asserted position.

In practice, HMRC will usually want to see documents showing what happened on the transaction and how the SDLT figure was arrived at. That often includes:

• the SDLT return or submission details;
• the signed contract or transfer;
• the completion statement;
• any corrected completion statement;
• correspondence from the conveyancer explaining the error; and
• proof of the amount actually paid.

If the taxpayer argues that the original SDLT figure was simply wrong, HMRC will normally expect clear documentary evidence showing both the original treatment and the corrected treatment.

Analysis

The position can be analysed step by step.

1. The first point is that an SDLT overpayment can often be corrected if the original figure was wrong. A clerical or conveyancing error does not prevent correction. What matters is proving the right amount of tax.

2. The second point is that HMRC is entitled to ask for evidence. If HMRC has specifically requested a completion statement, that is a strong sign that it considers the document important to verifying the claim.

3. The third point is that email correspondence from the conveyancer may support the taxpayer’s case, but it may not be enough on its own. HMRC often distinguishes between informal explanation and formal transactional evidence. A completion statement is usually treated as a more reliable record of the sums due on completion.

4. The fourth point is that the revised completion statement should ideally show the corrected SDLT figure clearly. If the corrected amount is said to be £1,400, the supporting documents should align with that figure and explain why the earlier figure was wrong.

5. The fifth point is that consistency across the evidence is important. If the completion statement, conveyancer correspondence, SDLT return details and payment records all point to the same corrected amount, the refund claim is much more likely to be accepted.

6. The sixth point is procedural. Depending on timing, the correction may be made by amendment of the SDLT return or by a repayment claim. The exact route depends on whether the statutory amendment period has expired and on the nature of the error.

So, the real issue here is evidential rather than conceptual. The buyer appears to have a potentially valid refund position, but HMRC may not process it without the updated completion statement it has asked for.

Outcome

The practical conclusion is that the buyer should obtain the updated completion statement from the conveyancer and submit it to HMRC with the corrected SDLT figure. If the original SDLT amount was overstated because of a conveyancing error, there may be a valid refund due. However, HMRC may reject or delay the claim if the evidence is incomplete.

In short, a conveyancer’s email may help, but a proper completion statement is likely to carry much greater weight.

Practical Steps

1. Ask the conveyancer for an updated completion statement showing the correct SDLT amount.

2. Check that the revised statement matches the transaction documents and the corrected tax calculation.

3. Gather all supporting documents, including the original completion statement, the corrected statement, conveyancer correspondence, and proof of SDLT paid.

4. Confirm whether the matter should be dealt with by amending the SDLT return or by making a repayment claim, depending on the statutory time limits.

5. Send HMRC a clear explanation of the error, when it was discovered, the correct SDLT figure, and why the original figure was wrong.

6. Keep copies of everything submitted and note any HMRC deadlines or reference details provided in its correspondence.

If the issue also involves a claim that the property was uninhabitable or not suitable for use at the effective date, readers should be aware that the condition thresholds are now relatively high following Amarjeet and Tajinder Mudan v The Commissioners for HMRC [2025] EWCA Civ 799. That means poor condition alone may not be enough; the facts must meet a stricter legal standard.

Conclusion

If too much SDLT was paid because of a conveyancing error, the position can often be corrected, but HMRC will usually expect proper evidence. Where HMRC has asked for a completion statement, obtaining an updated version is likely to be the most important next step in securing any refund.

Legal References Used

• Finance Act 2003
• Amarjeet and Tajinder Mudan v The Commissioners for HMRC [2025] EWCA Civ 799

This page was last updated on 22 March 2026.

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