Will a lender accept a Medival valuation for acquisition finance?
That is the lender's decision. Lenders set their own valuation requirements, may have panels of valuers they instruct directly, and may ask for a report addressed to them on their own terms. A Medival valuation is prepared for its stated purpose and addressed to the party that engaged it. Where finance is part of the transaction, the lender's requirements are worth confirming early, so the scope of the valuation can be set with them in mind.
Dealt with at length on Sale and Exit Valuations.
