CGT on second home with equity transfer

My wife has transferred some of her share of equity to me on our second home (using a solicitor so assume it's all legally correct). When selling I understand that the sale proceeds and selling costs can be split according to this equity split for CGT purposes to allow both of us to use CGT allowance. My question is how the purchase price is determined. She bought the property on her own but I assume for CGT purposes the purchase price for us both will be the same split as we currently have after the transfer so... Purchase price less costs was 160,000, Selling price less costs 210,000. If my beneficial interest is now 90% and hers 10% then I assume my CGT liability is 210,000 X 90% less 160,000 less 90% and hers is 10% of the same figures. If hers is less than the 6000 CGT allowance does she need to declare within 60 days? I assume I definitely will with my 90%. Also, my expected earnings in 22/23 are not yet known. I will of course estimate but will there be a correction on my self assessment form at the end of the year if it turns out the figure is different.

Hi,

As it is a joint property for married couples, the property is normally split 50/50 on any sale. You would need to submit a form 17 and declaration of trust for an alternative split. As there is no gain/loss at the time of transfer, when it comes to selling, the originally price at time of purchase is applied.

Guidance is at:

Capital Gains Tax: what you pay it on, rates and allowances

Declare beneficial interests in joint property and income

Thank you.