We had a family meal in the States. 20 family and friends and the service was terrible .It took 2 hours for a 2 course meal. The bill was a thousand dollars. The tip was. 200 dollars. This is a rip off . Please be aware if you go to the states.it is a myth if you think that service is better there. Obviously it depends where you go but it is all on the day. To expect 20 percent for doing your job is just not on. In Poland they expect no tips and service is fantastic.
Sounds like you and the Americans will both be much happier if you just stay in the UK in future.