Family of 7 visiting England for 14+ months, location suggestions?

My wife Sharon (Canadian) and I (American) are planning an extended stay (14 months) in England with our 5 Children. Her three, girls (ages 15, 13, 9) and my two, a boy (13) and a girl (14). We're planning on the kids most likely attending local schools as appropriate and as possible. This trip is primarily for them. Sharon is a school teacher, but won't be working. I'm a journalist/photographer and will only be doing freelance for Stateside outlets.

We'd like suggestions on locations, regions and/or counties to live in that:

- would be historic, educational, and rich in (true english) culture (without a McDonald's Burger Joint PLEASE!).

- has reasonably priced 4 bedroom homes and such to rent (let) in an area that is relatively close to other equally culturally rich areas.

- isn't too far off the beaten path allowing for easy (public) transportation (bus & rail) to London or another major metro areas.

- isn't economically distressed, but isn't terribly expensive to live in. 

We're looking at August for our move.

Thanks for any suggestions. Joel