Well I have to say that my experience with Cox's staff has left me feeling very likely to get Cox stuff again should the occasion arise. The spares person knew all about the drive and told me how to have a go at repairing/adjusting it. I was also amazxed at how darn simple the drive system is to get aqt and adjust, although it does not work quite as I had imagined. It seems to work on just increasing friction, whereas I thought the cone would actually travel in and out sloping plate to alter the gearing. However it obviously works, as Cox have used it for years.
The models you gave me are for newer machines than this by far. It's not even a 4000 after all, but an 800, series 2. So now I have no idea how old the poor thing is. Cox are emailing a manual for this actual model.
Nick