Quote Originally Posted by BernieNUFC View Post
Checked every Allen key bolt, every screw and removed covers to check wiring etc, went through every connector to controller and then to PC, everything is tight now, only one screw holding an earth wire was loose enough to take a nip up.
Have you checked for any axes binding. This is mostly likely cause.

After checking this I suggest you try running the same G-code at different feedrates to test if resonance is the cause. If it runs fine at lower feed rates and at higher feedrates then it's most likely Mid band resonance.