Just a quick word of thanks to werewolf for the pointer to
Château de Monhoudou.
Mrs FS and I flew in there on Saturday at the end of a great week's touring around France and loved it - a very friendly welcome from both the owners and the extensive menagerie of animals, a beautiful and peaceful location and a very good dinner in the evening. It made a perfect last stop for us but it's also well-placed for a weekend away from England.
There's a moderate up-slope at the start of 02 but it flattens off after about a third of the runway's 720m length. As you'd expect, it's a very aviation-friendly place: the owner keeps his own ULM on the strip and they're in the process of building a hangar.
Well worth a visit.