Bumpff

An origin suggestion: Bumpff - the term applied to anything involving papaerwork. It is an acronym for Brakes, Undercarriage, Mixture, Pitch, Fuel, Flaps, which was the landing checklist for piston-engined propellor driven aircraft: the term was then applied, initially by RAF types. When it subsequently came into general use it often lost its last 'f'.

Could be that this is first entry from SAMOVAR - SOCIETY that ASSIGNS MILITARY ORIGIN to VIRTUALLY ALL RANDOM SAYINGS

I think you could very well be right! Where did you collect this gem?
Just in case anyone doesn't know - "bumf" is certainly a shortening of "bum [in the British slang sense of 'backside'] fodder". (VSD)