If you had the house repossessed in August 1995, then six years from that is August last year, but it is the date upon which the house is sold that counts and that is what you need to discover.(posted 8099 days ago)Counting from that date, if its less than six years, then they have right to chase you, but as they are not mortgagees in the Building Society sense, they may have 12 years as the house purchase was a document under seal.
You need to take some qualified legal advice on this quickly - in the meantime, before you have done so, do not answer the letter.