A La Ronde (National Trust)

Another one I've had on my list since the 1980s. 
Pity I didn't go then though because you cannot go to the top floor now and see the shells which line the walls and ceiling there. It looks amazing up there.
I am playing catch up with the blips now and may not get through them all too fast.
Extra photo is a glimpse of the upstairs shell-fest.