It strikes me that these are Britishisms new or much more common in American English in the last decade or so:
     1. "spot on" in the sense of being exactly right
     2. "take a decision" rather than "make a decision"
     3. "go missing" in the sense of vanish or disappear
     4. "take a meeting" rather than "have a meeting"
I think I've noticed other expressions that I can't call to mind right now.  Not necessarily complaining. Anyone disagree or have other examples?