After swapping out 2 mice, I have realised what the problem is........ I have 2 PCs in my workshop. 1 dedicated CNC PC and another I do my designing and faffing on. When my CNC is doing is cutting I tend to do stuff on my other machine. However, the USB keyboard and mouse work really badly when the CNC is on. Must be some interference.

Before I start trying my own crazy ideas like wrapping the cables in foil and wearing a colander on my head, is there any better solutions to this?