Don't know for sure, but suspect you'd be best looking for flights from a local airport to Lorient, if they exist, then train to Vannes.
Heading there myself on Thursday week but (a) I live in the Poncy South, and (b) the car is already going to be full of unnecessary clothes, mad children and gorgeous, pouting SWMBO (in case she's reading this) /forums/images/graemlins/laugh.gif
Not a lot to work on re numbers,reason to travel etc etc but have a look HERE for rail options,a much more relaxed way to travel to France IMO and surprisingly cheap, no weight restrictions and very little waiting at check in.But I'm a poncey southerner as well and Ashford international is just down the road!