No evidence of failure
Thanks for trying. Much wasted time for all. Given that I had already deduced that it was an electrical fault and and almost certainly emanating from one of two switches I think your initial advice should have been not t proceed without access to a multimeter. To cap it all the door catch has been damaged in the attempt to remove the facia. So all in all a wasted and expensive experiment.
I'm not blaming you for the door. On the matter of the visual check I think you could have put more emphasis on the fact that in the event of no obvious evidence of failure (which I suspect is highly likely) your ability to help ceases. I suspect I would have stopped there and sought hands on assistance from a man with a meter. But as I said, thanks for trying.