1970 or '71. It was true. Well, I think it was 'cos I was with BOAC at the time (on 707-436s) and the story came to us from the VC10 fleet. F/E had bought a vacuum cleaner. Attached hose to sextant mount. Cleaned flight deck nicely until the hose sucked itself inside out and ended up thrashing itself to pieces on the top of the fuselage.
for some reason I remember that this happened between Melbourne and Perth - but in retrospect ... did the VC10 get down that way during those years?