Ever such a minor grumble, but I thought it might be worth mentioning...
Yesterday we went to Alton Towers with my 2 year old daughter, and her 2 year old friend. After Ice Age we thought we'd let them play together in Wobble World for half an hour, so we went in.
Turns out we had a slight problem, my daughter is 0.93 metres, her friend is 0.85 metres. Because Wobble World is split into two sections, one for 0.9m and above and one for 0.9 and below, the two children couldn't play together in the same section.
I appreciate that the same is true for all height restrictions across the park, but I'm not sure why my daughter couldn't have played with her friend in the younger area, particularly as there was only one other child in there, and they were all under parental supervision!