About 15 years ago, a friend took me and SWMBO on a very posh helicopter from Denham to Farnboro and back. With some er, interesting "pretend" landings at Farnboro. His clearance to fly thru the notional no-go area around LHR flightpaths was granted in about 5 seconds by the ATCO. I guess they are used to the Royalty flying in to and around Windsor.