The Pilchard Inn is on Burgh Island, a micro-island off Bigbury-on-Sea in South Devon that Agatha Christie was fond of. At low tide you walk across the sand to get there. At high tide you do not.
That is the part worth planning around, and also the best reason to go. Eat and drink long enough for the tide to come in and the ride back to the mainland is on a sea tractor, which is exactly what it sounds like.
Inside runs to cream stone fireplaces. Outside runs to benches and the water. Neither one needs improving.