Dave this first came to light (well my light) for me in 2008, I had just bought a new +4 and it had the random start issue then total failure. I rang the selling dealer Allon Whites and Phil Benfield advised I check the sensor ring said he had seen quite a few with the issue.
Back then MMC secured them in position with a thin cable tie, Phil’s solution was to fit a wider cable tie but I fitted two thick and one thin to fill the gap and hold the ring tight against the cowl plastic. It never failed to start again.
Maybe MMC finally got round to sorting it by fitting neoprene?
