I understand this is almost 2 years late, but this is the first time I've visited this particular board. Anyway, I can answer your question. The music played by Cadbury's band isn't any signed band in existance today. I just heard it while it's on ABC Family right now and I had instantly identified it as a song called the Song of Confusion. It was in an episode of the 1997 series Power Rangers Turbo called "Song of Confusion". The thing is, how did Warner Bros get a hold of a song that was made by the people at Saban Studios? Hope this answers your question.
Oh my gosh! I thought I was the only one who recognized the tune! I was like singing the Song Of confusion during that scene! 2016 edit: Saban Entertainment was one of the producers for the movie so that's probably how they got it.
Uh-oh. Not a word you want to hear in this house. Catch ya on the flip side.