We entered from Exhibition Road, this gave us logical tour throughout the exposition, starting from geology, volcanos etc.. Our tickets at the entrance was checked and people who hadn't prebooked a time was actually sent away.
The beginning of out tour was reasonably packed - not too many people, I guess because everybody was looking the dinosaurs, which was crammed. You kind of move there in line. Can't really understand the popularity of that. Also I didn't like the arthropod room, which was mostly pictures and moulages.
Overall it was great day with kid.
The details of the building itself were amazing.