It's not really a themepark, but the set for a show called splat-a-lot is still abandoned and it's the neatest thing ever.
Hiya, thanks for your message and sorry for taking ages to answer this!
I’ve seen a post on tumblr with a pics of this place and thought it was interesting. Can’t seem to find the post now. I’ll link it if I find it.
If anyone finds the post please link it here, I would like to see it again.