Share of profits upon sale of marital home

Hullo - Long-separated; divorced last year; own my own home now, and have joint ownership of the marital home. This latter is now being sold. The divorce court judge instructed that the nett proceeds be split 95%/5% in my ex's favour. I expect to have to pay CGT upon the sale. For CGT purposes, is my share of the profit deemed to be 50% of the overall profit ("joint" ownership) or 5% of it (what my profit actually will be)? Also, I understand that I need to declare what the value of the marital home was at the time of our separation. That was in 2013. How do I go about establishing that value, and what forms of evidence would be acceptable, please? Many thanks.

I have some info about this that are best towards me for you, if someone have better info please share here, For Capital Gains Tax (CGT) purposes, your share of the profit is based on the actual profit you receive, which would be 5% of the overall profit following the court's instruction. You'll pay CGT on this 5% share. To establish the value of the marital home at the time of your 2013 separation, you can use evidence such as a property appraisal from a qualified appraiser or historical sales data of similar properties in your area. These forms of documentation will help substantiate the property's value for tax purposes.

Hi GandalfTheGrey,

Please refer to the attached links to assist you with your Capital Gains query.  
HS281 Capital Gains Tax civil partners and spouses (2023)
CG22400P - Capital Gains manual: individuals: transfer of assets between spouses or between civil partners: transfers of assets following permanent separation, divorce or dissolution: Contents
Please also note HMRC can check the market value for you.  
Please see Post transaction valuation checks for Capital Gains (CG34) 

Thank you.