At Lake House, they grow as much of their own food as they can. Organic vegetables, beehives, cows and goats mean they could almost be self-sufficient. "That's important," says Sting.

Longleat House, near Warminster, was used as a makeshift hospital from November 1914 to January 1919. It treated more than 2,040 soldiers in World War One as well as victims of the 1918-19 Spanish ...