This summer we (me, my wife and three kids ages 10-18) are planning to spend our summer holiday in the UK. The general idea is to stay in the southern part of the country: take the ferry or tunnel to Dover, drive to Cornwall for a week's stay at the coast, then go a little further north (Cotswolds? Brecon Beacons?) for a week or so and finally spend a few days in London.

It's been years since I visited the UK (and this is the first time with the family) so any advise would be greatly appreciated. Places to visit, places to stay, places to avoid, alternatives to our destinations, the best way to discover London with a family without going bankrupt etc. Any ideas? The kids prefer to do as little as possible but with a pretty backdrop. My wife and I would like to be a little more active and like nature, hikes and city/village visits. Good food and nice beer are a must. ;)

Any pointers are very welcome!