I had a brain wave this evening. Took off the bevel drive and put the rear wheel on the bench. With the wheel off and dust covers out the bevel fitted perfectly on the wheel. I put the bevel back on the bike and offered up the wheel again. It still was a good fit. I took the wheel off and fitted the inner bearing and re-fitted the wheel. Again a good fit. Wheel off. This time I added the oil seal and re-fitted the wheel. Eureka!.....play. So now I know where the issue is. There seems to be few options for sizes of dust seals. I will have a chat with the parts suppliers to see what can be done.
I have also order the instrument pods that will house the volt meter and clock. Hopefully I will have them before the weekend.
I accidentally hit the start button whilst moving the bike; the ignition key was in the on position whilst I checked the volt meter reading, and the bike burst into life. So now the bike wants to run.