After many hours of trial and error we finally managed to get the rest of the seat mounting brackets in the right place so that the seat was in the middle and the doors would close:
We had to reverse one of the side mounts in the end to make it fit. Note we also have the brackets for the harness side mounts:
(Note th bolt on the side)
Test Seat Fitted - for now we have used Corbeau Club Sport (STD) GRP seats with slide rails:
Yes the doors do close :)