I struggled with the wheels. I got them off by taking the lip off the axle with a Dremel, but couldn’t get them back on by peening the end over with a hammer. All that did was damage the paint.
I ended up supergluing the wheels on, so they were fixed to the axle, but the other end was free to rotate. The axles could still move in the chassis too. Not ideal, but better than having a go at it with a hammer. Especially as the blue paint was from a “rattle can”, so harder to patch up than the red, white and black that were airbrushed and brushed.
Top coat is a matt lacquer, again from a rattle can. Paint job now seems fairly robust. I wouldn’t want to “brumm” the thing about, but as an ornament it can deal with being handled without chipping.