I have just came from London and have witnessed this in plenty of places there. Normally I would tip around 10%, but I'm more happy with this system, even if it

I have just came from London and have witnessed this in plenty of places there. Normally I would tip around 10%, but I'm more happy with this system, even if it's 20%. If they decide for you and ideally print up the amount in the menu then it's basically pricing it into the food which is how it should have always been.