Lucky you!
Hmm, firstly no speedos are necessary, no worries there
Book early/in advance if you have young DC for the Go-Karts/Pony rides (mine are 6 and 4).
Beg Meil itself is lovely, some nice restaurants and if you walk over the rocks, some lovely beaches that are very quiet.
Benodet is lovely, expensive to eat out there though.
Quimper is gorgeous, we stopped on the drive home and wished we'd spent more time there.
The beach near the campsite is gorgeous and we often stayed there until 7.30pm, it was still warm, though the sea is bloody cold. We found it best to go to the pool in the morning and the beach in the afternoon, though the slides are only on at 2pm, it is busy then though.
The camp shop is actually very well priced for most stuff, we went to Fouesnant (there is a "Dia" and lots of little shops in the town centre and a Carrefour just outside) for a bigger shop.
Umm, that is it I think.
We had a fab time, my DH is massively depressed now he's home and back at work and we've been deciding where we'll go next year, think we'll go to the Vendee, though I'd happily go back to Beg Meil to be honest.
Have a lovely holiday.