There's a great site owned by two Brits at Airvault (the birthplace of Voltaire) but it is just outside the Vendee and some way from the coast. No Mosquitoes though.
The site is called Courte Vallee you'll find details at www.alanrogers.com plus you could do a search there for all the Vendee sites and get a comprehensive report on each. Mossies should not be a real problem.
Thanks all, the trouble is when googling campsite Vendee all the big commercials come up and I am wanting something a bit less Blackpool, not that there is anything wrong with Blackpool if you know what I mean.