Something tells me a band aid while you wait thing you could do is have the speed control bypassed and use it on belt speed but then it may not be possible it seems like the sales bloke must have a service person who fixes the electronics by replacement my experience is its often cheaper if you figure in the cost of repairing over here its very high plus components. Theres a lot of hellfire and damnation going on how to denigrate threaten and demean. What was the new cost of the lathe 18mths ago amortised now value there is away to go to make a valued decision.
Trust me I wish you well good fortune and all that but calm reasoning with the full facts a little help from friends Gill. One thing I have observed is the location of the speed controllers can be meaningful.
Sorry from so far away I do feel your pain. Take care mate.
Peter.