There are no prizes for guessing what the highlight of the Disney on Ice Magical Ice Festival was, when it opened at the Genting Arena in Birmingham last night. Frozen has been a total phenomenon, the biggest new Disney hit in years, with ‘Let it Go’ being that song that you simply cannot dislodge from your brain. And last night in Birmingham, listening to the whole of the auditorium singing along with Elsa at the top of their voices, you realised you were in the midst of a very special moment. I don’t mind admitting I shed a few tears. The Magical Ice festival wasn’t just about Frozen. There was…