In reply to IPPurewater:
That's me all out of suggestions I'm afraid.
I think it depends when you're going a bit. We were down there one summer and you'd see loads of fields where a farmer had a sign saying camping-------> into a more or less empty field (maybe a tap or something) and they'd come round and pick up a fiver off you in the evening (when they remembered) but they're never really on the web or searchable...
That's probably more the kind of thing you're looking for, but it was getting on for 10 years since we were there so I'd be hard pressed to remember any details I'm afraid.