Do you need exchange contracts, completion statements and passports for an SDLT review?

Introduction

People asking for a Stamp Duty Land Tax review often want to know what documents are actually needed. A buyer may already have completion statements and signed authority forms, but not every exchange contract. They may also wonder whether identity documents such as passports must be provided.

This usually comes up where an adviser is checking whether the right amount of SDLT was paid, preparing a reclaim, or reviewing more than one property purchase. The answer depends on what issue is being reviewed, but some documents are commonly more important than others.

The Question

A property buyer says they have already sent signed authority letters and completion statements for a number of property transactions. They do not hold signed exchange contracts for every purchase and ask whether those contracts are needed, whether the adviser can obtain them from the conveyancing solicitors, and whether passports for the joint purchasers must also be sent.

Nick’s Explanation

Nick’s reply was brief and practical: he thanked the buyer for sending the signed authority letters.

In substance, the position is that:

• signed authority letters can allow an adviser to request papers from the solicitors acting on the purchase;
• completion statements are often useful because they help confirm the transaction completed, the price paid, and the amounts collected on completion;
• exchange contracts may be helpful in some cases, but they are not always essential for every SDLT review;
• identity documents such as passports may be needed if the adviser must carry out client due diligence or verify authority, but that depends on the nature of the engagement.

In anonymised terms, Nick’s response was effectively an acknowledgement that the signed authority had been received and could be used to progress matters.

The Law

SDLT is charged under the Finance Act 2003. The core rules on land transactions, chargeable consideration, effective date, and returns are found in that Act.

For practical review work, the key legal and procedural points are usually these:

• the effective date of a land transaction is important for SDLT purposes, and this is commonly completion, although substantial performance can sometimes bring the date forward;
• the contract, transfer, completion statement, SDLT return and any relief claim documents may all help establish the correct tax treatment;
• an adviser acting on behalf of a taxpayer will usually need written authority before a solicitor or another third party releases papers;
• anti-money laundering and client due diligence rules may require proof of identity in some circumstances, depending on the service being provided and whether the adviser is required to verify the client.

Where a case involves a claim that a property was not suitable for use as a dwelling, the legal threshold is now relatively high following Amarjeet and Tajinder Mudan v The Commissioners for HMRC [2025] EWCA Civ 799. A buyer will usually need strong evidence of serious physical problems affecting suitability at the effective date, not merely disrepair, dated condition, or the need for renovation.

Analysis

The first point is that not every SDLT review needs exactly the same documents. What is necessary depends on the issue under review.

If the question is simply what was bought, when it completed, and what price was paid, the completion statement and transfer paperwork may already answer much of that. Those documents often show:

• the property being purchased;
• the completion date;
• the purchase price;
• fees and SDLT collected on completion.

Exchange contracts can still matter. They may help where there is a dispute or uncertainty about:

• the terms of the transaction;
• whether anything was included in the consideration;
• whether there was linked consideration or another related deal;
• whether substantial performance happened before completion;
• whether any special conditions affect the SDLT analysis.

So, if exchange contracts are missing, that does not automatically stop a review. It simply means the adviser may need to obtain them if the legal issue cannot be resolved without them.

The second point is authority. If the buyer has signed authority letters, that usually puts the adviser in a position to contact the conveyancing solicitors and request the file documents needed for the SDLT analysis. In practice, solicitors often require a clear written authority before releasing contracts, completion statements, SDLT submissions or correspondence.

The third point is identity documents. Passports are not part of the SDLT legislation itself, but they may be needed for regulatory reasons. An adviser may need them to verify the identity of the person instructing them, particularly where the adviser is formally retained, handling a reclaim, or dealing with sensitive tax records. Whether passports are required is therefore usually an engagement and compliance question rather than a substantive SDLT rule.

The fourth point is that the document list becomes more important if the case involves a technical relief or a reclaim. For example:

• multiple dwellings relief cases may require evidence of the layout and use of the property at the effective date;
• mixed-use cases may require plans, title documents, photographs and contract terms;
• uninhabitable dwelling arguments require strong contemporaneous evidence of condition, and the threshold is now high after Mudan.

In those cases, the adviser may need more than just the completion statement. They may need the contract, title register, transfer, valuation evidence, photographs, survey reports and correspondence from the time of purchase.

Outcome

The practical answer is that completion statements and signed authority letters are a good starting point. Missing exchange contracts do not necessarily prevent an SDLT review, because they can often be obtained from the acting solicitors if written authority has been given. Passports may be required for identity verification, but that depends on the adviser’s compliance obligations rather than on SDLT law alone.

Practical Steps

• Check what type of SDLT review is being carried out and ask for a document list tailored to that issue.
• Provide signed authority so the adviser can request missing papers directly from the conveyancing solicitors.
• Send the documents already available, such as completion statements, SDLT returns, title documents and completion dates.
• Ask specifically whether exchange contracts are essential in the particular case or only desirable.
• Ask whether identity documents are needed for anti-money laundering or client verification purposes.
• If the case involves condition of the property, gather contemporaneous evidence from the purchase date, such as surveys, photographs, invoices and lender correspondence.
• If arguing that a dwelling was not suitable for use, assess the evidence carefully in light of Amarjeet and Tajinder Mudan v The Commissioners for HMRC [2025] EWCA Civ 799, because the threshold is now relatively high.

Conclusion

For most SDLT reviews, signed authority letters and completion statements are often enough to begin. Exchange contracts may still be needed, but they can usually be obtained from the solicitors if authority has been given. Passports are a separate compliance issue and may be required depending on the adviser’s verification process.

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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