Due diligence is the process of testing the claims behind a proposed purchase. Keep a record of what is confirmed, what remains an assumption and who is qualified to resolve the outstanding questions.
Separate the workstreams
Use different sections for ownership and legal issues, physical condition, finance and the intended use. GOV.UK's home-buying guide for England and Wales distinguishes the work of a conveyancer, surveyor and mortgage adviser. One person's report should not be assumed to cover another's specialist role.
Turn each claim into a question
If a listing says a property has development potential, ask what evidence supports that statement. If an appraisal assumes a rent, ask where the comparison comes from. Save the answer and its date, including any caveats. A missing answer should remain visible rather than silently becoming a positive assumption.
Record costs beyond the asking price
Prepare a dated list of professional fees, planned works, financing and ongoing commitments. Obtain appropriate advice about taxes and permissions. Test whether the purchase still meets your own criteria when a cost increases or a proposed use is not available.
Set a decision checkpoint
Before committing, review unresolved matters with the relevant professionals. Decide which findings require further investigation, a revised offer or walking away. The purpose of the file is to support a considered decision, not to guarantee a return or replace professional advice.
Editorial review: 14 October 2026. This original Property Perpetuity guide replaces the imported text; the original archive publication date is retained.