[1] Originally known as Hawnes Park it was built c.1725 for John Carteret, 2nd Earl Granville, a prominent statesman and remodelled and expanded several times since by his descendants.

It is constructed of red and white brick to a square plan in two storeys with attics and slate roofs.

Francis Thynne's second son was Lt Col. Algernon Carteret Thynne (1868–1917), DSO, Royal North Devon Hussars, of Penstowe, Kilkhampton, who was killed in action in Palestine during World War I,[3] and whose monument by Sir William Goscombe John R.A. (1860–1952) survives in Kilkhampton Church.

A portrait also existed there of Sir George Carteret, 1st Baronet (c.1610–1680), Governor of Jersey, who purchased Haynes in 1667 and whose grandson was the husband of Lady Grace Grenville.

After Clarendon School merged with Monkton Combe School near Bath, Somerset in 1992 the property was sold to the Radha Soami Satsang Beas British Isles (RSSB), an Indian sect and is still (2019) still occupied by the associated organisation Science of the Soul.