In reply to sheelba:
We hired a field at Grizedale Campsite last summer for my 40th and a mates 30th.
They have a field down the road from the main site with a couple of "eco loos". Great spot and you don't have to worry about disturbing the neighbours and we got them to do a hog roast on the Saturday night for us all which was absolutely spot on!
Can highly recommend them.
http://www.grizedale-camping.co.uk/