We've used Booking.com > France
Found the descriptions & facilities quite accurate including parking
I generally have a month in France in the summer and also use Booking.com for the journey down (and back) - combined with Street View, I always find secure parking. I am on the other side (east) this year which won't be any good for Bordeaux.
Two years ago I passed close to Bordeaux and these might be close to your route.
Chateau de Razay
Hotel le Saint Gelais
Chateau de Lacenne
