1944 (Dec 28) Plain envelope with vertical crease containing letter on Free French pictorial paper to St. Germain des Fosses from Soldat G.1108 Leon Varaire, French Air Force H.Q., 15 Queensberry Way, London SW 7 bearing GB GV1 3d tied scarce Marston Moor RAF P.O. / York cds & with PC 90 continuous Crowns OPENED BY EXAMINER 6616 label..Normally the closed address of P.O. Box 236 would be used for security purposes however it seems that this was relaxed in the latter stages of the war in Europe. Marston Moor RAF P.O. 24 May 43 – 1 Nov 45 had been used by 1652 HCU (Heavy Conversion Unit) until June 1945 training pilots & crews from smaller bombers to the larger 4 Engined Handley Page Halifax bombers.