you can buy a new set of number plates on eBay for £15.00 including delivery.
The thing about ebay plates is they are illegal. It just gives plod a chance to pull you over, especially if your personalised plate has unrealistic spacing etc.
No doubt plod will have a crackdown and you leave yourself wide open. Its ok doing that on your own car, its your responsibility.
But do that on a motability lease car is a different matter. I do the same as glos guy, its easier and less hassle.