the built in air stairs were heavy and fragile .we were glad when they were withdrawn
I'm sure you're right about the Vanguard problems but in the industrial atmosphere of 70s (when it was a question of whose turn it was to go on strike today) there was many a time that we were glad of those airstairs and the reversing props which made us independent of tugs and stair drivers.
Landed one a.m. in a Merchantman with a complete hydraulic failure (no brakes or steering) and dutifully asked for a tug.to clear 28L (as it was then). When informed that it would take half an hour for a tug to reach me, decided to carry on and eventually parked on the stand using the props alone.
Part of base training syllabus for converting captains was practising three-point turns.
Happy days!