The handle is held to the shaft by a tiny and almost invisible grub screw (underside when handle in neutral). With a vibrating saw tool I cut a slot in the bluw plastic vertically downwards to allow access for the allen key to the screw. How they got it on in the first place is a mystery. Once it was off I cut a circular hole around the handle in the plastic to allow the handle to fit deeper on the shaft. What I still don’t know is how to adjust the handle friction.