I remember a very unusual use of a conductor on a Green Line Leyland National on route 708 in the 1970s. The driver had been having trouble with the doors and was having to get out of his cab to operate the emergency door switch at stops, so when we arrived at Two Waters Garage he went in to report the problem, probably expecting the bus to be subbed. Instead he came back out with a spare conductor, who had been given the duty of operating the doors!
London Country also hired some elderly Royal Blue Bristol MW coaches (in National white livery) during the mid-1970s when vehicle shortages had reached a critical level. These operated on routes from Dunton Green Garage and carried conductors, as the doors could only be operated manually.