You might in your own opinion backed up by the two valuations think that the property was undersold, but all the lender in possession is under a duty to do is obtain the best price available at the time from prospective buyers. They can prove they have exercised that duty by proving adverts and putting a notice in the paper that they have had an offer of £x and any higher offers to reach them by Y date.(posted 7512 days ago)Methinks make an offer well before the court hearing - if accepted, you at least will not then be landed with some possibly hefty court costs.
I cannot guide you, but I have known offers of 10% and 20% of the shortfall be accepted. Try - you never know!!!