Archie Bellville is a second cousin of the present Duchess of Grafton, née Olivia Margaret M Sladen (born 1978), as they are both great grandchildren of Gerald Carew Sladen (8 III 1881-21 IV 1930) and his wife, Mabel Ursula Orr Ewing (19 IV 1887-1963), who was a daughter of Sir Archibald Ernest Orr Ewing, 3rd Bt (22 II 1853-21 IV 1919) and his wife, the Hon Mabel Addington (d. 30 III 1942), daughter of the 3rd Viscount Sidmouth.
Camilla Wilson's great grandmother, née Elizabeth Ursula Cadbury (20 VI 1906-2001), was a member of that landed gentry (and chocolate manufacturing) family. Through this connection, Miss Wilson is a step third cousin of the present Duchess of Argyll, née Eleanor Mary Cadbury (born 26 I 1973), as she is a great-great granddaughter of George Cadbury (19 IX 1839- 24 X 1922) and his second wife, Dame Elizabeth Mary, née Taylor, (24 VI 1858-4 XII 1951), while the Duchess is a great-great granddaughter of the said George Cadbury and his first wife, Mary Tylor (1849-27 IV 1887).
Camilla Wilson and the Duchess of Argyll are both fourth cousins of Ruth Margaret Cadbury (b. 14 V 1959), Mrs Nicholas Gash, who has since 2015 been the MP (Labour) for Brentford and Isleworth, and is a great-great granddaughter of Richard Cadbury (29 VIII 1835-21 III 1899), an older brother of George Cadbury.
Camilla Wilson's aunt, the former Emma Elizabeth Stanier (b. 13 V 1957) is married to Simon John Buckmaster (b. 1 IV 1956), a younger brother of the present 4th Viscount Buckmaster.
Richard
Unfortunately, I do not currently have access to BLG 1972, but from my recollection the article on CADBURY of Northfield concentrates on the descendants of George Cadbury (19 IX 1839- 24 X 1922). Elizabeth Ursula was his eleventh and youngest child.
George Cadbury's second son (Elizabeth Ursula's stepbrother) was another George Cadbury (7 IV 1878-27 IX 1954). He married Edith Caroline Woodall (1876-1935) and their second son, John Christopher Cadbury (28 XI 1908-25 VI 1995) married Honor Mary Milward (1909-1957). John Christopher Cadbury and his wife Honor were the parents of Peter Hugh George Cadbury (b. 8 VI 1943), who married Sally Strouvelle in 1969; they were the parents of Eleanor Mary Cadbury, who is now the Duchess of Argyll.
Elizabeth Ursula Cadbury's eldest brother of the whole blood (i.e. the fourth son of George Cadbury (19 IX 1839- 24 X 1922), but his eldest son from his second marriage) was Laurence John Cadbury (30 III 1889-5 XI 1982), who married Joyce Mathews, by whom he had six children, including Sir (George) Adrian (Hayhurst) Cadbury CH, DL (15 IV 1929-3 IX 2015), Chairman of Cadbury-Schweppes, Sir (Nicholas) Dominic Cadbury (b. 12 V 1940), another Cadbury Chairman, and Jocelyn Benedict Laurence Cadbury (3 III 1946-31 VII 1982), MP (Conservative) for Birmingham Northfield from 1979 to 1982.
I think that some of the above names should appear in the BLG article on the family.