Thanks for all the encouragement
I've done a few bits this weekend, not as much as I would have hoped..
I finally managed to remove the small circular mount on the dashboard shaft that the steering cog fits to. It was mounted using two small grub screws (that were rounded out). I've no idea what the grub screws were made of but they were really really hard. I went through 3 hacksaw blades trying to saw through the mount!!
The dashboard is 90% back together now and not a bit of rust in sight:
Looking at my other dashboards, it seems I've mounted the bracket with the pot on upside down. I'll fix that that shortly.
I also assembled the pedal base/back box - looks nice and tidy:
I'm going to strip the fans down shortly and clean out all the old cr*p from them. One of them was certainly struggling to spin.
The dashboard previously had a fan mounted on it - do I need to bother re-fitting it? The two OR2 dashes I have don't have them on and I don't think they have suffered.