Problem solved.
Thanks for the suggestions.
On the lock assembly there is a piece of black plastic that is part of the child lock override button. This pivots on a pin. It would seem that it had jumped the pivots and was floating free. It can’t go anywhere as it jams the locking mechanism. With a small screwdriver it clicked back on the pivot. After reassembly everything locks and opens as it should. I can’t see how it popped off in the first place, maybe a previous owner slammed the door too hard. Anyway, saved the price of a door actuator.
Incidentally, the inside door panel comes off very easily with a plastic pry tool, but putting it back on is not so easy, it tricky getting the top part of the door trim over the metal of the door, opening the window helps a lot but its still difficult.
Hope this help someone.
steve