Hello, I'm Keith and happy to help you with your question. It maybe not as not as bad as you think; for starters you have an Annual Exempt Allowance of 11.1K! Was the property ever let out and, if so, did you declare the rental income to HMRC? When you say 'vacant over the years' were you in possession? Was it your sole or main domestic residence? Finally why were you not living in it, was the absence work related?