Brittany is ok but weather can be hit or miss, if you do stay there I would also recomend les menhirs or the grande metarie (not sure of that spelling).
Weve just come back but decided to go further south, I would really recommend st jean de monts, its a cyclist heaven with 500k of
trails, great beaches and pretty reliable weather, try one of the siblu sites, les maison or something similar.
have a good un.