Keep property evidence separate from financial assumptions

Label the origin of every number

A registered completion price, an agent's asking price, a contractor quote and a buyer's maintenance allowance are different kinds of information. Putting them in one spreadsheet does not make them equally reliable.

The PropertyMetrics workspace keeps connected public records in the research area and user-entered finance inputs in the cost model. Preserve that separation when exporting a case or discussing it with an adviser.

Stress the assumptions that can move

Mortgage rates, rent, void periods, service charges and works costs can change. A single base case hides that uncertainty. The current model shows a simple rate-and-rent downside case, but it does not replace a full cash-flow forecast.

• Obtain achieved-rent evidence rather than listings alone.
• Use written quotes for material works.
• Check tax treatment for the buyer and transaction date.
• Retain an emergency reserve outside the purchase-cost estimate.

Stop when the decision needs regulated advice

A research tool can organise facts and assumptions. It cannot decide whether a mortgage is suitable, provide a survey opinion, interpret a title or file a tax return. Escalate those questions to appropriately qualified professionals.