From his father's first marriage to Mary Clarke, he had many half-siblings, including William Bouverie, 1st Earl of Radnor,[1] Hon.
His father, a son of Sir William des Bouverie, 1st Baronet and his second wife Anne Urry (daughter and heiress of David Urry of London),[2] dropped the prefix "des" in his surname by Act of Parliament on 22 April 1737,[3] and inherited Longford Castle and his father's baronetcy from his brother Edward in 1736.
[6] His father's sister, the former Jane Bouverie, had married John Allen-Pusey and when he died without issue,[7] Allen-Pusey's sisters selected Philip to inherit the estate (which had been bequeathed to Allen, who took the additional name of Pusey, by his uncle, Charles Pusey, who died in 1710).
[9] On 20 August 1798, he was married to Lady Lucy Cave (née Sherard) (1771–1858) at St George's Hanover Square Church.
Lady Lucy was the widow of Sir Thomas Cave, 7th Baronet (former MP for Leicestershire) and daughter of the Rev.