Worth remembering that the whole purpose of vehicle registration plates is so a vehicle can be easily identified by the authorities. Not so your car can be identified by your mates.
If you do anything to deliberately make your registration read differently to what it is supposed to read, and you make it more difficult for the authorities to identify you, you should know the authorities aren't going to be too pleased about that, and if you push your luck they will catch up with you eventually.
Whether they fool the ANPR system or not is besides the point, as we're not solely reliant on ANPR for vehicle recognition anyway. The human eye still plays sn important role. If it were all about raising revenue the easiest way to do that is to force everyone to buy your plates from the government like you do with your passport.