It's not too late to question the debt B&B say you owe them. Read through the details on this website about the kind of letters you can write and the information which you need to be looking for.(posted 7810 days ago)Before the B&B can lay hands on the equity in your current property, they have to have a money judgement again you and for this they would have to go to court. Although they are threatening you with court action, it is not always likely that they will go ahead with the threat, its usually just that.
Write to them and start asking questions, and don't hand over any personal papers no matter what they threaten. Even if they did issue proceedings, the civil procedure rules say that they have to justify their claim - they'll have to prove what you owe with documents.