Capital Gains sale of French house - HMRC Form required?

Which paper form do I ask for for Capital Gains on sale of French house - sa106 is all I can find? Also I had to have tax representative for French tax and a substantial amount of money is being with held as Social Tax for France but the tax representative has informed me there is new regulation in French Tax that if I can supply certain proof of use of recognised 'social schemes'' in UK such as NHS and State Pension I will get the money. So far nothing has satisfied as proof. Can you advise how to obtain this proof for me?. I am 79 years old in June and do not work so do not pay any National Insurance. If I cannot supply the form of proof required can I deduct this amount with held as part of French Social Tax - if not how long must I wait to get the money being with held before deducting it for UK Capital Gains? Many thanks.

Hi Moira Doyle,

The SA106 is correct.  
All income from abroad should be declared on the Foreign Pages.  
With regards to supplying proof from NHS / State Pension, please contact DWP:
Contact the Pension Service

Thank you.