Morning guys - I wanted to post a successful resolution and thank @WillAdams and support and the rest of the guys at C3D.
As everyone says support is first class. 8 days after posting this a new X/Z carriage has travels 3000 odd miles to me in England.
Whilst I had to dismantle and re-build my X/Z carriage, I can confirm this has resolved my issue. Interestingly my original one is of a different spec and I measured between the holes and found I had a slight difference - 0.9mm on the right and 0.7 on the left - compared to the new one sent to me.
It appears the original was slightly out of tolerance - that said it has been usable till late.
However what I’d like to highlight is the constant improvement I see from C3D. Whilst I do have an early revision of the Shapeoko 3, many companies would say this is good enough. Wait a year then knock out a new version. Not these guys! They improve and re-build their contents feeding improvements in from all sorts of places.
The original X carriage does the job very well, but the new version has multiple enhancements, such as fixed motors and tension bolt for the Z axis belt.
Now these enhancements might help with assembly but they also help give us a more rigid assembly that is easier to maintain.
So hats off you you! Thank you and I will post some pics when I have some time