He in 1743 sold it to Arthur M. St Leger, 3rd Viscount Doneraile, who conveyed it in 1748 in legal title not equity to Charles Unwin (as his trustee) — so on death in 1750 without issue, Doneraile's will confirmed his wish it pass to cousin Elizabeth St Leger 'until marriage' — she then married Major Ralph Burton. On her marriage the estate re-vested in trustees, who sold it in 1753 to the Thomas Villiers, successful diplomat and second son of William Villiers, 2nd Earl of Jersey. Thomas Villiers married the heiress to the wealthiest branch of the Hyde family whose 1st Earl was a minister under Charles, Charles II and grandfather of Anne and Mary. Thomas was soon created Lord Hyde (Baron Hyde of Hindon) for his diplomatic services in 1756 and in 1776 the Crown revived the old Earldom and raised him to 1st Earl of Clarendon (second creation). The fourth earl was a statesman, diplomat (architect of the Quadruple Alliance of 1834), Secretary of State for Foreign Affairs, Lord Privy Seal, Chancellor of the Duchy of Lancaster, President of the Board of Trade, Lord Lieutenant of Ireland and gained non-occupational titles KG and GCB. Consequently, regular guests in the mid and late nineteenth century included Queen Victoria, Prime Minister Lord Palmerston and Edward VII. In the early 20th century, death duties, a form of taxation introduced in 1894 by the Liberal Government, was placing an increasing financial burden on landed gentry and was responsible for the breaking up of many large estates across Britain. In the 1920s, in order to reduce their tax liabilities, the Villiers family decided to sell The Grove, downsizing their holdings to their estate at Swanmore, Hampshire. Also at around this time, nearby Cassiobury House was sold off by the widow of George Capell, 7th Earl of Essex in 1922 due to prohibitive death duties. After the sale, The Grove was then used as a gardening school, a health centre (National Institute of Nutrition and College of Dietetics), a riding school, and a girls' boarding school. It was the wartime headquarters of one of the Big Four consolidated railway companies. It became a management training centre for the British Transport Commission and later British Rail. In 1996, the estate was acquired by Ralph Trustees Ltd, at which time the mansion was extended and converted into an hotel.