In reply to DreadyCraig:
As wild camping is certainly discouraged in the Peak District, there don't seem to be any obvious ones.
But as said there are some old stone barns and shooting cabins where you could put your head down for the night. They almost certainly won't have fires/beds and due to fire risks, outdoor fires aren't allowed in the dark peak.
Whether or not you will get a good night sleep is entirely at the landowner/managers discretion, if you turn up at 4, cook your tea and get drunk and loud, I'd expect to be moved on by dusk. If you turn up at dusk put your head down you might be OK. A passing farmer might move you on at dawn.
Edit: I can't recommend any specifically, I can't remember the locations/states of the ones I'm vaguely aware of. Some certainly have timber/stone roofs I would not want to sleep under.
Post edited at 12:00