If she hasn't yet signed contracts, or signed contracts subject to survey, then of course she is entitled to try to renegotiate based on the results of the survey. However it is not necessarily her solicitors job to do this- she can very easily do it herself- get on to the auctioneer, tell him the result and ask him to ask the vendors to reduce the price to reflect the survey report. Changing the price on the contract is a matter of getting a biro out....if agreement is reached beforehand.