Hi Steve,
I would almost certainly drive.The freedom of having your own car to trek around and see the sights is a good idea.Have no idea of ferry costs as I'm irish!
This will be my fourth year staying at campsites along the atlantic coast.First one I'd recommend is Beg meil L'Atlantique near fouesnant.It's approx 3 hours drive from Cherbourg/Roscoff and has direct access through a small forest onto a lovely beach.There's a fabulous waterpark and a decent take away on site but the site is off the beaten track.It has the most imaginitively designed playground for kids with ships and lighthouse.My kids keep begging to go back.The weather of course is never guaranteed in Brittany.
The second one is in the Vendee near the resort of St Jean de Monts.
It's called Zagarella and is small, lively with a good atmosphere.It's about 4 miles from St Jean de Monts beach which is the most massive beach I've ever seen.The waterpark in Zagarella is perfect for smaller kids and the whole complex was very safe for little ones. My son was 5 and it was ideal for him.There was no problem with the 5 hour drive down.
I think the best thing to do is get a keycamp brochure or a canvas one and have a look through them, choose your campsite and book directly with the site itself.
Sins

Hi! If you are looking for a campsite check out http://www.camping2006.fr as this is a large directory of camspites with online availability..Irish too so no idea about ferries..sorry! Palmyr-Loisirs is a good campsite in the Charente Maritime as is Sequoia Parc..closest town is Royan. Other aiport possibility would be Poitiers which is about a 2 hour drive away. Bonne chance!

Thanks to both of you for that

Check out Brittany Ferries: http://www.brittanyferries.co.uk/index.cfm?articleid=50 They sometimes have good offers regarding accommodation and car ferry.

Have been to the Vendee a number of times and haven't had a bad experience yet. Normally get an overnight ferry from P/mouth to Caen which leaves loads of time to get to St. Jean, St. Hilaire, St. Gilles etc. Virtually free motorway and dual carriageway all the way so its OK for kids (mine have been going since they were 3 and 5). The ferries cost a bit more but shop around for cheap offers.

Ended up in Sol a go go (St. Hilaire) last year for less than £600 all in, (14 nights including ferries) and had one of the best hols ever.

The beaches here are magnificent and there is masses to do around the area (and a bit further afield - so take the car).

What's as important is being a Celtic cousin. The French people around here absolutely adore the Welsh, so make a point of letting them know!!

Bob / Pilot - thanks. Nice to know someone like sthe Welsh! Only problem is I can't speak French OR Welsh.

Hi we are having the same problem! see the chenac ref!!!- i can't seem to get a flight from l'pool to bordeaux - do you know which airlines are flying from there?
Thanks

Have seen a couple of sites which look OK. Acapulco and Le Clars Plage bot hnear St Jean de Monts. Does anybody have any experience of these?