He was s of Sir Bryan Cosmo BONSOR 3rd Bt 1916-77 and Elizabeth 1920-95 d of Angus Valdimar HAMBRO 1883-1957 scion of that gentry family of The Hyde and his 2nd w Vanda Dorothy Julia 1885-1981 d of St John CHARLTON 1843-1919 and Elizabeth Bronwen 1854-1941 d of Hugh Robert HUGHES 1827-1911 and Lady Florentia Emily LIDDELL 1828-1909 d of 1st Earl of RAVENSWORTH 1797-1878 and his w a gd of 1st Marquess of HERTFORD 1718-94, gt gd of 2nd Duke of GRAFTON 1683-1757 (who was gs of King CHARLES II), 3xgt gd of 1st Duke of BEAUFORT 1629-1700, etc. He m 1971 Susan Anne b 1949 d of Flt-Lt David Henry Lewis WIGAN 1924-2006 scion of that gentry family of Drewitts and as his 1st w (her 1st h) Anne 1924-2017 (Lady Pease) d of Lt-Col Reginald Francis HEYWORTH 1896-ka1941 scion of that gentry family of Bradwell Grove and as her 1st h Hon Moyra MARJORIBANKS 1902-95 d of 3rd Baron TWEEDMOUTH 1874-1935 (gs of 7th Duke of MARLBOROUGH 1822-1883 (who was also gf of the British PM Sir Winston CHURCHILL), etc) and Lady Muriel BRODRICK 1881-1966 d of 1st Earl of MIDLETON 1856-1942 and Lady Hilda CHARTERIS 1854-1901 d of 10th Earl of WEMYSS 1818-1914 by his w a d of 1st Earl of LICHFIELD 1795-1854, etc, and had two sons and a dau.