I am not a legal eagle but I doubt that a national regulator is a party in any case where the alleged offence took place outside their jurisdiction.
In the same way that you will not be 'done' in an English court for a speeding offence on the Continent.
If you bust a French TRA they will have to prosecute you in France. Fairly well publicised case about 10 years ago where a French parachutist fell through a British glider wing. The chaps were invited to go to court in France.
IIRC they went but if they hadn't gone I doubt that they could have been forced.
Certainly don't think that the CAA could have taken any action against them.