Whoever designed the mount for the Tomtom Rider version 1 should be shot.
Mine was constantly resetting itself or showing the card not inserted sign and not charging on the bike. Also the connectors on the back looked badly worn due to the Rider shaking in the mount. I sent the Rider and mount back to Tomtom and they replaced it under warranty but that was not going to stop it happening again. It was then I came up with my cunning plan.
I made a bracket that would hold the Rider firmly at the bottom of the mount and also mounted the mount on anti vibration rubbers. It has now covered many thousands of miles with no problem. I have attached a photo to show the mod. I hope it may help others.