I’m not sure why you’d want to do anything without permission? It’s a lease car, not yours. Ask them, if they say no then that’s the end of it surely? If you do it anyway your insurance could be invalid and you’re also risking your ability to continue to use Motability. You can ask them via live chat on the website. We’ve had permission for mud flaps, removable tints and solar power battery charger on current car. They wanted exact details on each of them before approval and details I’m told were added to the account. Had to give them a reason for the tints which was to keep the dog cool.