Oh dear , i think i already knew what your answer was going to be.
The extension was NOT in print when we bought the house, but now i am a widow i have no funds to fight the french law courts.
This means my house, when it eventually sells with be worth nothing.
It was valued at probate 2011 for 280,000 and had been revalued by one Estate Agent to put OM at 135,000 INCLUDING 6% FEES
i will be lucky to come away with under £100,000
If there is no specific law i can refer to then i have no case