CGT on mixed use property

I’m selling a mixed use property which has been my permanent residence. It is a flat above a dance studio. How is the CGT tax worked out on it. Is it by percentage or value of flat. Flat was valued at £210,000 and sale is £393000, but I estimate the % split is more like 35% in area. Also I’m being paid on deferred amount, £193,000 now, £50,000 in 3 months and rest in two years. Thank you

Hi Carolaj,
It is based on the value.
You will need to have a value of the flat at time of purchase in order to work out the gain on the dance studio in order to report it.
For declaring any gain, it will still be the full gain and then you apply for deferred consideration as not all the funds are received at point of sale - CG14850 - Deferred consideration: introduction
Thank you.