Did you ask the garage if you could bring in parts for them to install? Over here thats rather unusual and sometimes seen as downright rude.
Yeah they are cool with it, when I had tyres fitted to my Clio they asked me if I already had the tires to fit right off the bat. These guys seem to be all about service, not making a quick penny off the parts. Besides, since they are already ordering some parts and things they wont mind me passing them a few extras to fit at the same time Im sure.
If I lump the cambelt change in it all in its less labour overall and Id rather do that than keep taking the car back to the garage.
Oh and France = teh fag0try.