Hi Zh, thanks for the response. I had seen that video quite a while ago, and I balance that way. Anyway, I stripped the axis down again and rebuilt. It is quite a bit better now as I found that the bull gear has quite a high spot covering about 30 degrees. I've adjusted so it's just tight here and OK on the rest.
There must be a market for spare parts as I'm sure there are loads of old mounts that just need a new set of gears and a tune up.
Once again, many thanks.
Phill