No reason to be surprised – you just need to file a flight plan (and get it authorised) between 24 and 2 hours prior to departure. If its a local flight starting and finishing at the airport of departure (I recall not going further away than 3nm form the airfield) you don’t even have to do that. This of course applies only to the outer zone in which N Weald is located.

Phew that’s a relief, I had visions of Andy doing yet another Spitfire dig for the TV :p