With the tyre removed I could finally mount one of the wheels up on the lathe to check if it fitted. Fortunately there was a few mm to spare. With the wheel mounted in the chuck it was only a few minutes work to face the hub off and remove the spigot so that the hub flange I made sits nice and flat. I'm pretty happy with how it has turned out.
I still have the other hub and wheel to finish off. Then I can look at making the front hubs up