http://www.rafmuseum.org.uk/mileston...tary/1947.html
"30 April - 1 May 1947
A de Havilland Mosquito flown by Squadron Leader H.B. 'Micky' Martin (later, Air Marshal Sir Harold Martin) and Squadron Leader E.B. Sismore establish a new London-Cape Town record, covering a distance of 6,717 miles in 21 hours 31 minutes at an average speed of 279mph"
Vfrpilotpb, the photo you have (my guess) would be an aicraft (supporting the record Mosquito flight) on its return trip to Blighty.