Thanks Jazz. It's great to hear from someone knowledgeable in this area.

It did surprise me that the guys in the motion control Facebook group seemed to think it was normal. I'll continue investigating things with the manufacturer and see what they say.

Given they're in China, if they suggest stripping it down is that a difficult thing to do? I imagine it would be relatively simple, the only part I'm not sure about is the ball screw part with the bearings (not sure of the name). Fingers crossed they also honour the warranty.