The Home Counties Flying Club at Sudley was a flying club where Lancelot Seymour was taking flying lessons in The Case of the Brilliant Pupil. At the time of Biggles' investigation into the activities of Seymour, the club secretary was Tommy Clewson, an ex-R.A.F. Flying Officer. Seymour had signed up first for "A" licence and then for "B" licence instruction at the club and on the day of Biggles' visit, was scheduled to make a second attempt on the final test of the "B" licence, a cross-country solo night flight from the club to Lympne using one of the club's de Havilland Tiger Moth aircraft. Seymour was arrested just before takeoff, along with his accomplice Tod Mills. Mills had just passed him a packet containing pajamas which in reality was stuff with treasury notes, robbed from the Euston-Crewe express. The packet also contained a small parachute. Quite likely, Seymour had planned to divert during his flight and drop the parcel somewhere over France.
Both the club and Sudley are fictional places.