What are the difference between the London and New York Billy Elliot shows?

I saw the show in London on vacation and they say something about the london show and broadway show are different but I can't find where someone tells you. I'm just curious :)What are the difference between the London and New York Billy Elliot shows?
In one they have authentic accents, in NYC possibly voice coached linguistics..... other than that, just minor staging and blocking differences to accomodate the physical theatre surroundings....What are the difference between the London and New York Billy Elliot shows?
Besides the cast? Some choreography can be a little different, maybe a song is left out or put in.