I worked on a campsite in the South Vendee in the mid 2000’s. From that experience, I can whole heartedly say if you want a beach holiday then the Vendee is ideal, not too far to drive (5 hours from St Malo aprox) There are lots of big sites, each with entertainment and plenty to do.
The beaches are excellent if that’s your thing and bucket loads of touristy days out. Round fort boyard, Ile de Re and a fair few themeparks I seem to remember.
There is also miles of off road, cycle path up and down the forest between the beach and the land. Billiard table flat and ideal for wee wheels. It’s also out of the sun so good for getting shade in the heat of the day.
My experience is 10 years out of date now, but Canvas Holidays used to have far superior tents. Much bigger, with better headroom.
Oh and I also had a lot of fun on Zagarella when I visited. fnar fnar.
Possibly one of the best summers to date!