Back after a break - put the outer front upright of the door on, and its hinges. Followed that up with the structural support leading off top of picture: actually did a decent job welding this one up! On to the 2nd box of electrodes, soon: spoke to the shop and they said that yes, they too also do a first weld, then grind it down the centre and "finish" it off with a smooth run. Added in the cross-piece and the inner upright. This door is going to be a bit awkward: pieces marked in green are where the outer box has to go. It was much easier to do the other door (even with the mistakes made).
Also, as an aside: after putting in only the one support piece between the outer door frame and the front suspension (top of picture) the whole front frame stiffened up immensely, leaving the windscreen frame flexing like mad. This is good, because adding in the actual glass will result in a very sturdy frame.