Shayne, my Boy, what an excellent find! I have always been pretty sure that nothing was broken here, simply that I had introduced a fault. Now, the easy thing as mentioned before is to just pop two old bulbs back in and go for a spin. I have to confess I haven't tried indicating whilst CC was set but as the side lights and brake lights are in the same bulb, it's likely that this is a replica of the fault shown in the video where it's the indicators tripping the CC.
I shall report back once I have chance to get on the road. Only wanted LEDs in there really to save power and hopefully be more rugged in relation to rough roads. But hey, maybe good old fashioned filaments are the best thing