We found a great supermarket - the Super U. Simply go thru Mulsanne and keep going, and about 8 kilometers along there is a huge Super-U that was almost always near as damn it empty, with huge car park and petrol station, complete with LRP fuel too.
They ran out of 33 by the Friday and I picked up the last few Chenet on Thursday, but managed to check my email and oogle a few cars in the foyer, inc a nice old M3 and a "forumula france" whatever that is