Can anyone shed light on this? Capital Gains Tax

[Sausagedognamedmash]

Hoping someone knows the answer to this as I'm asking on behalf of MIL and have no clue myself.

MIL bought her house in 1990, she lived in it until she sold it in 2022. When FIL died in 2005 she bought a second home, initially for BIL to live in for a few years with the idea to have this as a nest egg/pension pot. BIL moved out in 2022 and MIL moved in.

MIL hates the house and wants to sell up and buy somewhere she loves just for her. However we are confused as to the capital gains tax she will be paying on this as it wasn't her primary residence for the past 17 years but is now and will be until it's redecorated and she can face the idea of selling again.

Having looked into it there appears to be a lot about how long she's lived in the house and some sources say it will be primary residence and exempt after 2 years of living there, however from what I've read I'm pretty sure this isn't true. I am clueless to this and it's like the blind leading the blind here so if anyone has any knowledge on this and can advise I'd really appreciate it!

Wait a couple of weeks (absolute worst time for tax advice today!) and then get professional advice, it won't cost much compared to the cost of the house and could prevent a very expensive mistake.

www.gov.uk/tax-relief-selling-home
This is very easy to follow.

Selling at a profit, which will be large given the timescale, will attract CGT. This will reduce with length of time it's been her primary residence or only property owned. 2 years out of 19 won't bring it down very much. Seek professional advice.

Thank you all. I will talk to her and try to get to the bottom of why she dislikes the house so much as financially at least it makes sense for her to stay there. I think she just can't equate it to anything other than BILs home so it doesn't feel like hers and likely never will.