TomTom kindly sent me one of the clips, and all went well, especially when I was on the bike. However I'm in Australia on hols and yesterday took a trip around the harbour. I had the Bandit attached to the end of a £54 extending stick, and had it fully extended and was filming, when the Bandit unexpectedly came away, and fell 12 feet onto a metal deck. In my panic the stick followed it down and is now at the bottom of Sydney Harbour. Thankfully the Bandit didn't go overboard, and despite an almighty clang as it hit the deck, is all working ok.
On inspection, the anti-rotation clip had come partially loose, and undermined the spring clip, resulting in the detachment of the unit. Users be aware, the anti-rotation clip does work loose over time, and does not 'click' into place satisfactorily. Design fault methinks?