I've made a small amount of further progress with this and I have encountered the first problem, which I think I've solved. The problem is that the wheels aren't really designed to be removable. There is a strip at the bottom of the axle guide that is designed to be folded over to retain the axle. That works, but it can only really be done once, do it too many times and the half etched line will break. The other thing obstructing the removal of the wheels are the brakes. The idea is that the wheels are fitted and used as a guide to place the brake shoes. Then the pull rods are fitted, again with the wheels in place. However, there are pull rods on both the outside and the inside of the wheels.
What I am planning on doing is the following. For the axle retaining strips I will remove them now and glue them in place once everything is put together after painting. The brakes are a little more complicated, but I think I should be able to make them as a separate assembly. Solder them together, but don't attach them to the chassis. That way, with a little care, they can be fitted and removed as needed.
I have also decided that now is as good a time as any to paint the wheels. The tender is less critical in this regard, but I don't want to have to paint the driving wheels after I've sorted out the mechanism. I want to fit them once and once only, so they need to be painted before I need them. I spent a few days struggling to get straight pieces of mashing tape to follow the curve on the edge of the wheel. Today I went to the local hobby shop and bought some liquid masking film. I had all the wheels done is less time than I had spent on one with the tape. I laid them out on cardboard (courtesy of Amazon) and held them down with double sided tape. I gave them a coat of red primer and when that was dry a coat of Precision P53 Crimson Lake. I smuggled this back to the US of A on the way back from trip to Ally Pally in March. Don't tell BA! I hadn't actually sprayed enamels with this compressor before and since it's pretty small I figured it would need thinning. As we all know, expensive models are the best place to experiment with painting techniques. I've found that "airbrush ready" paints need to be thinned almost 1:1 paint to thinner to get good results. The PP paints are thicker than the other paints I've used (Tru-Color), so I went with 1:2 paint:thinner. This worked fine, but 1:1 would have been better. I also managed to miss half the spokes, so another coat will be needed, probably tomorrow.
Wet paint and direct sunlight make these look quite light, but now that they're drying they look more like the colour they should be.
