First job for today was to find out why the handbrake lever appeared to hit a mechanical stop about a quarter of the way up.
After removing the passenger seat (again) it became obvious that the shoulder of the small turnbuckle I fitted was contacting the handbrake lever body. Simple fix was to add a couple of washers as spacers and bingo... we now have an operational handbrake!
I also fitted the steering wheel to the boss with the proper bolts ("proper" as in "right length")