Thanks v much for the suggestions. I haven't fixed the problem yet but have certainly found something amiss with the ball screw, it does not feel as smooth as it should, and the slides do feel tight. Hopefully when I follow up in the new year all will be revealed.
All the best guys.

Using an electronic edge finder held in the machine spindle, the machine does not report the same coordinatesat every contact between the edge finder and the workpiece. However, a dial gauge positioned against the end of the worktable does return to the same position at every contact. Conversely, re...