I'm talking about Britains' and the newer models which don't have an axle. I've employed the grip and twist technique for many years on the models that do have an axle.
The central hub is metal and seems to be a rivet of sorts. Obviously, without this hub, the wheel then isn't as useful.
As can be seen in the photo attached, I've tried gripping it in a pair of pliers but only end up chewing up the paintwork.
When the model is split in half it might be possible to drill it out from the inside but, this is what I'm trying to avoid.