Hi Andy,
I recently went on a farm stay holiday with Featherdown farms, it's basically luxury camping. You can find out a bit more about my trip
here and find out more information about Feather down itself
here
Alternatively you could check out some villa rentals with
Meon Villas, they have a free flight offer on at the moment or
Cottages 4 You now have a great portfolio of self catering accommodation in France, Spain and Portugal plus you get 5% off with Take the Family.
Something else to consider would be
Canvas Holidays, they have some resorts in Brittany that are geared up for young families. You will also receive a 5% discount with Take the Family.
Good luck with your search. Do let us know how you get on.
Lucy
Take the Family