The history of the camera and its survival is complicated by the lens - an English Ross (London) 53mm f1.9, in itself quite rare. It is mounted in a hand made helical focus mount as originally it would have been a bellows camera lens. It is a machinist's solution, well made and accurate but basic. I can only speculate that the original Zeiss Biotar 4cm lens was damaged when the camera was salvaged from an aircraft during the war and whatever was to hand was pressed into service. If it was post war salvage, surely a correct lens would have been easy to source - easier than this solution at any rate.
Against that is the unmarked condition of the mounting lugs which suggest that it was never mounted in an aircraft. The serial number of 047008 implies an early production example - 001 is still owned by Berning as a showpiece. It may have been souvenired immediately post-war by someone who mounted his own lens. Unless someone has access to records of this exact camera, we'll never know.