Either or

My client and her boyfriend jointly purchased a house 20 years ago for a total of £50 000 which they used as their only or main residence.

They never married and 14 years later (i.e. six years ago) they separated when my client moved out and purchased another house where she still lives.

One year ago the ex-boyfriend moved out and our client purchased his half share of their house for £80 000. Our client now hopes to sell that property for £220 000 and has asked for capital gains tax advice.

This seemed pretty straightforward but it then occurred to me that there was more than one way of calculating this and I should be grateful if Taxation readers could advise on the correct method of calculating the gain.

Do I simply deduct a cost of £105 000 (£25 000 plus £80 000) from the...