Low Class

TC Electronic Switch-3 https://www.tc-helicon.com/Categories/Tchelicon/Accessories/Footswitches-and-Remote-Controls/SWITCH-3/p/P0DAK#googtrans(en|en)

From the OP: "Quick background - I play in at a music trust every Saturday, in 3 different ensembles. Each requires a room change so I have to move my gear every 50 mins or so. " Doesn't sound like he's going through any dirt track car parks. I've been using this setup on 3 different cabs over the past 2 years and I will never be without it. Works quite well in parking lots. Now it will be limited if the cab weighed much more (50lbs+) or if used in unusually rough terrain, but otherwise it is quite up to the job.

+1! Here's my rig with a similar product: https://tchweb.com/three-stage-removable-surface-mount-extension-handle-with-wheels/ I looked at the one you linked to also before I bought this one as it seemed to be a little more heavy duty. This is my 3rd cab now with this setup.

If the TH500 sounded good to you with that cab then don't waste your time and money trying everything else.