Thanks for the offer Bart but my DIY skills are sub-par to say the least, I have the handle unit the same as the picture on
https://www.joolca.com.au/pages/hottap which tends to slide around on the things I can find to put it on.
It's 100% my fault, not blaming the product at all, just looking for a solution.
My current best idea is bending up some alluminium in a shallow S shape that is nearly as wide as the handle and bolting it to something so that once hung the unit won't move around so much.
Just need to find the bolts, alloy, something to bend it with and somewhere to bolt it to, easy.