Christmas hours have always been very good. I remember previous years all rides being 0 min queue in the evening. but the long hours weee there to help with the Santa grotto, as demand for that is so high.
Yeah they could probably get away with 12noon to 8pm really. Although maybe those with younger children won’t want to stay late so an early start is better for them. I guess you get two types of group, those doing 10-6 at most with CBeebies age kids and those doing the later hours with older kids (or no kids).