BOAC,
Never tried it (but I will ask to now if time can be found) but I believe single
autopilot landing is no prob with norm landing flap of 30 or more appropriately 40.
The nose up trim applied during dual channel is intended I believe to give the elevators a bit less work to do for the auto go-around, which of course has to be fairly agressively instigated if flown from the Cat3 DH of 50ft.