Having now reassembled my Selfix 820 thanks to information from members of this this forum (see previous thread), I thought I should show the result.
Making the missing pins proved to be quite a job - my old lathe is a bit sloppy for jobs this small - but I succeeded at the 5th and 6th attempts. I used mild steel and polished them. It now self-erects very well.
There were other problems. One of the plates which hold the door pivots, and the strut mountings and springs, had come adrift, and allowed the spring to damage the rear-most fold of the bellows. This looked like an ideal subject for 'Liquid Electrical Tape' applied outside and inside. The bellows looked otherwise very sound, but while checking the repair I found three other tiny light-leaks in the corners of the bellows, so I applied a coat of liquid tape down the inside of all 4 corners and the bellows now appear completely light-tight.
I stripped and cleaned the shutter and lens. There was quite a bit of fungus on the back of the rear-element, but it cleaned well and the optics look very nice.
I'll put some film through when I get a chance, but I don't currently have a scanner that will take medium format so it might be some time before I can properly check the results.