Nothing wrong with the grey cabs per se and if you can't fold the head and tail, then it's not living easily on Argus. Had forgotten the interim was the "spare" eight folding heads on Mk3s.
I think it's probably to do with lifting potential Ebola cases on stretchers shoulder high to get them in the door, as opposed to walking up a ramp. Not a case of suitable / unsuitable, more which is going to be less of an embu88erance.