I used to go to Centerparcs a couple of times a year! (Whinfell Forest)
It's beautiful and serene up there, and I do like everything they have going on on the complex, though I do find it horribly overpriced in terms of food etc. There again, you can always go into the Lake District to buy food or go to a restaurant.
My absolute favourite bit is the spa at Aqua Sana. It might well be my favourite place ever, and, athough I don't tend to stay on the complex anymore, I do book a spa day a couple of times a year and just go up for the day and stay in a cheap B&B in the Lakes.