Hi Derek,
You need to remove the electronic pack to get at the bottom door carriage adjustment. With only 3mm or so gap I would probably leave it alone but if you feel the need then I would only adjust one door. To maintain a uniform gap it is usual to adjust top and bottom door carriers.
On the several times that I have fitted new doors, the gap seems to be wider with the replacements doors fitted. I believe that later models of these machines have rubber buffers in the centre of the carriage slides (as do replacement slides) and new doors are manufactured to achieve a slightly wider gap to take these buffers into account. If that is not the answer, it is indeed strange that the gap grows every time I fit new doors!
This is a bit of a balls aching job and you will probably regret starting it for the sake of a 3mm gap!!