I've just spotted this from the advert:
"You can take a flight of fright on Vampire to soar through the trees of Transylvania, enjoy Dragon’s Fury’s spectacular spin underneath the stars, or incur the wrath of Rameses’ Revenge with Chessington’s favourite rides available to enjoy under the dark cloak of night."
This sounds to me that not every ride will be available in the evenings at this year's event. I do hope I'm wrong!