Peterh, thanks for the Aussie invention information, very similar to the Ace but uses wire cables and more suited to be used with the trials knobbies.
Nebulous you mentioned loosening spokes, as a side comment I rechecked my brand new bike spokes with a spoke tension wrench after 2 hours riding, my skill is learner trials and so no jumping off large logs and rocks etc, but the results were all over the place, glad I did this check and retension ( similar results to my KTM EXCF 500 though). By keeping the spokes tight it could help prevent damage and distortion to the rim when clamping/transporting as a suggestion for others.
All good feedback and ideas, appreciated.