With mojo fully restored in between going for my Covid jab I cracked on and got the brakes assembled and soldered in place. I left the crankshaft from the brake cylinder loose for the moment just in case I do find a way to fit the brake cylinder.
I made up a couple of adjusters from some telescopic tube, filing the larger pieces into hexagons to represent nuts at each end.

Next up is fit the sand pipes then to work out how best the motor will fit with the body on. The latter should tell me whether I will be able to fit the brake cylinder after all.