Elsewhere on this site are some snippets of information about this. I read, for example, that it is extremely rare for a lender to force the sale of a property in such circumstances, because lenders basically don't like shafting each other; it is also very rare for a lender to put a 'charge' on a property.(posted 8422 days ago)Please read this site (start with 'Repossession') because if you are a strong person you should definitely fight for your rights.
However, if you were less than honest with your current lender about a previous repossession, then I think that you need to face up to this. Perhaps start by taking advice - the CAB are very caring and non-judgemental (and their advice is free). By the way, if you did tell your current lender that you had previously been repossessed, I would be very interested to know what its reaction was to this.