As a long-time resident of north Norfolk, Antony Gormley has for years been familiar with Houghton Hall, the Palladian mansion built in the 1720s by Britain’s first prime minister, Robert Walpole. In more recent times “this extraordinary British Versailles”, as he refers to it, has become a renowned outdoor-and-indoor exhibition space for sculptors such as Anish Kapoor, Ernst Gamperl and Richard Long.