Hi Stephen,
Not exactly next door, but around 50 km and 50 minutes from the port - is the beautiful "Camping Les Capucines" site at Tredrez-Locquemeau
It's quite a small site, about 70 pitches - two good toilet blocks - a small shop and bar - with great views. The site is around the head of a valley, with terraced level pitches - and (almost) everyone gets a view. And a cool breeze usually blows up the valley during the day, keeping the heat off.
In the village of St-Michel, there are a couple of good restaurants, creperies and cafes, and one of the biggest beaches I've seen - with the tide out it's a 1+ km walk across the sand to the water.
Robert