OK, I've completed one side. I found that my car had the nut for the top mount for shoulder belts but not the mounting bracket for the anchor point for the reel.
I got the bracket off a '92 Golf at the local wrecker's. I drilled the spot welds but still had a hard time getting it off. A cold chisel, hammer and tire iron eventually got it out.
I positioned the bracket, marked the holes and ground the paint off the areas where the welds would go.
My car had a previous repair in this area with fibreglass, so I couldn't weld everywhere I wanted along the front, so I put a couple of stitch welds along the rear because I figured that would be the area with the highest forces.
I had to get the plastic panel for the rear pillar at the same time i got the belt and bracket.