CGT on former marital home after divorce and then renting out

Could you please offer some guidance on CGT and my wife's old marital home? She bought it with her then husband in 1997 and after splitting up continued to live there till 2004. She increased the mortgage to buy him out of the house, meaning the mortgage was now more than the original purchase price of 1997. A few questions. Can this extra borrowing re her divorce be taken into account when calculating CGT as she is now (hopefully) selling up? Can it be added to the original purchase price re calculations (if that makes sense?). As the only person to profit from that extra borrowing was her ex husband. Presumably she can also claim PRR for the 7 years she lived there? In addition, after moving in with me in late 2004, she rented out her old home on a buy-to-let mortage. She has carried out multiple improvements over the years including new windows and boiler. Can these be offset against CGT or if they were already offset against her Income Tax in previous years is that a no go? Thank you kindly for any advice

Hi,
The mortgage is not an allowable expense for capital gains and it is based on the original purchase price. her share would be 50%. the additional 50% would then be the value of the house when she bought out her ex husband. PRR is allowable for the period she lived there. she cannot claim for the improvement as rleief has laready been claimed through the rental side.
Thank you.