VR motion controller inheriting transform and rotation constraints from object

morning all,

as above really. I have a rotary dial that I want to interact with using the motion controller. Nothing happens until you pull thr trigger, only then does the dial rotate around the Z axis from a central pivot point. however, despite the fact that everything on the object is locked down except the Z rotation, once the motion controller trigger is pulled the dial behaves very strangely

Do i need to have the controller inherit the constraints, or is there a better way?

thanks for your help, its driving me round the twist