Thanks for the follow up Rick and the advice. I'm hoping to get stuck into this at the weekend and discover more and will post what happens. Current position is that the rear doors lock and unlock normally. The front passenger door the same manually but the mechanism was a little stiff, and the actuator solenoid is non-responsive. Driver's door is the conundrum.
The manual key will not open the manually locked drivers door. The interior handle also doesn't open the door, unless I leave the key in the barrel at the lock position (fully counter clockwise). Then two pulls of the interior handle and the door pops open. Now the door is unlocked, but the key is trapped in the barrel in a position just 20 degrees or less clockwise from full lock. As long as I leave the key in the lock in that position, the door opens and closes normally. The only way though to get the key out is to return it to the lock position slightly counterclockwise. I can now remove the key which renders inside and outside handles inoperative and the door is locked again.
The only way to open the drivers door from the outside is to connect the battery and turn the key clockwise at the same time as operating the fob button and pulling the handle. Could I possibly have a faulty superlock situation? Further investigation clearly needed. I have a new passenger door actuator ready to fit so hopefully I'll have three working doors soon and can really focus on the drivers door then. So odd that all was well until the battery went flat!
