I used to go to Elveden Forest one all the time when I was younger. It was really good so far as I remember. It's good fun and great for a bunch of people to hang out. There a loads of different pools, with slides and things, as well as Sauna's and all that if you're into that kind of thing. There are loads of other sports, a bowling alley and a disco (although, admittedly, it was pants). There are plenty of restaurants to choose from too.
Overall, it's good fun - I'd recommend it.
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