I replaced the two rear door handles while also putting on armour door plates. I started left rear and worked my way round. I had a little bit of difficulty with the locking mechanism on the drivers door, but if you move the door mechanism so it thinks it is closed it is all good.
I then went round to all the doors and checked them...... Guess what, the very first one, the rear left I have put in incorrectly. So I can open it. If I pull the pin up and then try either the indoor or outdoor handle, it pulls the pin back down instead of opening the door....

I'm guessing that I will have to take the inside panel and membrane off, in order to release the mechanism, so that I can open the door and unscrew the handle.......
Unless anyone knows a cunning trick?