In the UK if a bill comes to £65.54 for example, you give them £66.
Thats the only sort of tipping we do. Obviously some times you might give them an extra £5 but its very rare.
The price is the price. Hence why I don't agree with gratuities personally, the company should be paying its employees the correct living wage and not having them rely on gratuities. On my recent cruise I tipped the room attended $15 as she was exceptional. The bar staff got a $1 tip after every 4th drink in the same place and the waiter/assistant waiter in the main dining got $10 each as they served us every night.
Gratuities are a big no no in my opinion, a bit like a service charge on a bill. If they want you to pay extra then include it in the main price from the offset.