Was on the M40 and clicked on the cruise, just sat back in my seat and I heard this sort of 'tock' noise, like the sound when you press the door lock button. Cruise light when off and the car started slowing down, so I accelerated back up to my original speed and tried to re-activate, nothing happened, no light, no cruise. I thought maybe a relay or fuse had blown but I kept trying it nonetheless, nothing happened. Got to my meeting, the car was parked up for a few hours, on the way home it came back to life and has been working as normal since. Any ideas?