Thank you Neil, appreciate the advice. In two minds now as to whether to bother, as the main reason for doing it was to take off the drive wheel to soak it and free up the rollers which were all seized solid. But in the end a lot of blowtorch and tapping got them all free. On the other hand it would be good to check everything over while I have the tracks off to rebuild them, so suppose I should just bite the bullet!
Ps not quite sure what came over me but just acquired another MG5, so will be in touch soon with another shopping list I expect.