PS Been looking at some old threads and Sue Edwards (Social Policy officer with NACAB) mentioned the case law of Barrett v Halifax Building Society - a high court case in 1995, which I believe supported the right of a borrower to sell at a loss.(posted 8498 days ago)Since then there have been two pieces of conflicting caselaw: Cheltenham & Gloucester plc v Krausz (1996 Court of Appeal) and Polonski v Lloyds Bank plc (1997 High Court case).
She ends, 'You will need legal advice to proceed on this one.' But don't forget that you can get free advice at you local CAB (Citizens' Advice Bureau), and if you have Home Contents Insurance, or Trade Union membership, or even a credit card like Barclaycard, then you will get some free legal advice via these channels too. Though personally I find the internet (and this site in particular) the best mine of information.
Let me know if this is of interest. I think I have some relevant emails archived somewhere on the case law.