Stevef and Flap40.
That is the one the Armstrong Whitworth AW 23.
Sir Alan Cobham pioneered research on the probe and drogue method, and gave public demonstrations of the system. In 1934, he founded Flight Refuelling Ltd. (FRL), and by 1938 had used an automatic system to refuel aircraft as large as the Short Empire flying boat Cambria from an Armstrong Whitworth AW.23.
