Been and took various measurements from the bearing edge to the brake disc bolt holes and to the outer edge of the wheel rim. All measurements are equal, so am happy with that, must be as advised by Rob R - a poor casting and the machining has made it true.
Unfortunately I don't have access to any machine to check run out. Will sit wheel back in swing arm and see if I can determine if it's run out it true.
It all started due to an advisory at mot stating that the brake disc is slightly warped, so it took the opportunity to replace brake disc, chain and sprockets. Brake disc appears to be level by using the edge of a steel rule.
Craig