Posting here for traffic, sorry. 
We're coming to the UK in October and want to take ds to an amusement type park. He's a small 4 year old so I feel like Alton Towers etc will be lost on him.
Legoland I haven't been to in about 10 years but I wasn't that impressed.
I remember Efteling being incredible when I was his age, is it still amazing? I'm guessing flights to Holland would be cheapish.
Anywhere else incredible?