Hi Jay
Welcome back. I have a Graduate with a Eurotherm inverter and I love it. My inverter sits on a shelf above the lathe and to all intents and purposes the lathe looks like the original. But the gain from having VS is enormous. I have only changed belt positions on the odd occasion and find I can do most items on one pully. My inverter, however, is a very early one and has no adjustments on it and at the highest speeds the motor plays up a bit which is stopped by slowing down a bit. Most of the newer type have adjustment, dont ask me what it does as this aspect goes right over my head, so I doubt you would have this problem with a Haydock. Go for it you will not regret it.
Roger Groom