John Fowler holidays is a faily small, low budget, butlins style holiday. The accommodation is chalet style, never caravans, and is basic but comfortable. The parks they have are all situated in Devon and Cornwall. All of the holiday parks have free entertainment, swimming pool, shop, crazy golf, resturant, take-away and more. I have been with John Fowler many times and I cannot believe how good the are for the prices they charge.
A week in June can cost from £180 for a chalet for two adults and two children. This can rise to about £250 in peak season but it's still cheap. I get sent a new brochure every year and an oppotunity to book early and receive a £50-100 discount on the holiday this brings the costs down to £130. Not Bad at all!
I don't have any children but I have been with a friend and with my partner before and have always thoroughly enjoyed the holiday. We have stayed at different sites in Cornwall and Devon and have found the service has been very good throughout.
They provide everything you need for a self-catering holiday and will help with anything else they can.
Oh, and you can take a well behaved dog if you so require!