I don't know how impressive it'll be after working with dragons - but have you ever been to a safari park? It's not adrenaline-rush exciting, but it could definitely be interesting. They've got animals from all over the (muggle) world in huge exhibits that mimic their natural habitat and you can drive right through without any bars between you and the animals.
Once it gets warmer I think there's a few places in the UK that do white-water-rafting and other water-based activities that I'd imagine you could do with your leg.