Thorpe Park has lots to offer, you can whizz upside down on Colossus or get soaked on Tidal Wave. You run the risk of getting wet on the Ribena Rumba Rapids which were great fun. There are some gentler rides like the Carousel, the teacups, the banana boat. Then there is the Vortex which really is scary and adiable to complete before food.
Food is expensive and chain stored - KFC, Burger King etc. Water and Ice cream are pricey but of course essential. I'd advise taking your own supplies where possible, though carrying a big bag is a pain unless you have someone to hold it whilst you're on the rides !
We're definitley going back next year when they've finished building Nemesis !