We stayed here last week for one night as a stopping off point, in Warwickshire near the Leicestershire border: http://www.ukcampsite.co.uk/sites/details.asp?revid=5989 It's a quiet campsite (though we were there midweek); it’s on a slope (you will probably need chocks) surrounded by countryside with some lovely views on one side. Very cheap at £10 per night (including hook-up), but the facilities are fairly basic - loos, cold water only and no showers. Well located for Twycross Zoo, Bosworth Battlefields, and Conkers. The site is very difficult to find! Using the postcode on a sat nav sends you to the wrong place. There are no camping signposts, and not even a sign for the farm as you drive up the track from the road (you enter via another farm!). The owners were very helpful when we rang to say we were lost! We’d happily stay here again now we know where it is!
Definitely read the directions on the UKCampsite page otherwise you will get lost, even if you are local!!
I have read them on the website and I know where it is I used to drive past it when I worked over that way