Mount Offham is understood to have been constructed between 1840 and 1870 by the Rhodes family, cousins of the late Queen Elizabeth II. The royal connections continued when the house was owned in the 1950s by Baron Plunkett, master of the Queen's bedchamber. He was also the chairman of the Society for the Protection of Ancient Buildings and with his aesthetic sense, he is credited with the beautification of Mount Offham (then called The Mount) by the addition of glazing bars,