OK, I have managed to open the passenger door. I undid the hinges, luckily the door strap/stay on that side is missing, so was able to pull it far enough out so that I could then fiddle with the internal lock and the catch released. So, one problem solved. On the drivers door, there is a door stay, so I do not think that the hinge method will work. We have tried pushing, pulling, tugging etc on the drivers door, while moving the handles, but it will not budge. It is a 1970 MK4, so basically the same body as the 1500 ... I think!