A lot of American expressions end up being used in the UK anyway because of the influence of movies, music, TV shows, etc. I don't think we Americans know a lot about what's going on in the world around us, so not as many UK expressions make their way over here. "Cheers" is a good example of that; we still say it only when making toasts and at no other time. The average American will be able to figure out what you mean but won't know that it's a British expression.