I've been playing with this again today with the motor off the machine still and got what looks to be a pretty decent (not perfect) tune.

So I loaded up UCCNC just to jog the motor and see what it was like. When I jog the motor it will happily rotate in one direction but when I try the other way it is fighting itself and just judders a bit and doesn't really rotate at all....

Does this indicate it may be a hardware issue rather than the tune?

I will try the motor on another drive tomorrow and see what results I get to start ruling some stuff out.

But could this be down to an issue with the motor or encoder? or does it still seem likely to be my lack of skills with the tuning software?