Phil: I'm guessing you're talking about Hibaldstow. It's not in Doncaster's (or anyone else's) airspace but all activities there have to be conducted with the permission of Humberside ATC because their approaches/departures pass a short distance to the east of Hibaldstow. Humberside will have a formal Letter of Agreement with the club at Hibaldstow which specifies how they are to maintain contact, permissions required and the area within which parachuting can be carried out.
Parachute clubs which are the sole operators at an airfield normally use the generic parachuting Air-to-Ground frequency 129.9 but I see Hibaldstow has its own frequency 129.925.
NS