Some notes:
Julian Alan Lowther Hector b. 1958, Nairobi, educ. Univ. of Bristol (Ph.D. 1981, hon, D.Sc. 2014), head of Natural History Unit, BBC Studios; 2nd wife (m. 1996) Mary (née Colwell) a BBC Radio producer. Their two sons are 'Colwell-Hector'; some sources indicate their father also adopted this surname.
Andrew N. Caldecott seems to be Andrew Hilary Caldecott (1952-), director, Spoken Ink Ltd (publishing). He eldest s. (3 s, 1 dau.) of (John) Andrew Caldecott (1924-1990), of Elmdown Farmhouse, Ramsbury, Wilts., educ. Eton, Trinity Coll., Oxon. (B.A.), merchant banker and solicitor (partner, Druces and Attlee 1954-69), chairman of the M. & G. Group, Lt, King's Royal Rifle Corps, by his wife Zita Ursula Mary (1932-), dau. of Peter Gilbert Marie Sebastian Belloc (1904-1941), Capt., Royal Marines [s. of (Joseph) Hilaire Pierre Rene Swanton Belloc (1870-1953), of King's Land, Shipley, W. Sussex, the famous writer] by his wife Stella (1901-1995), dau. of - Benson.
J. A. Caldecott s. of Sir Andrew Caldecott (1884-1951), of Pier Point, West Itchenor, Sussex, educ. Uppingham, Exeter Coll., Oxon. (B.A. 1907, M.A., Hon. Fellow 1948), Governor of Ceylon 1937-44, Governor of Hong Kong 1935-7, G.C.M.G., C.B.E., K.St.J., F.R.A.S., F.R.S.A, by his first wife (m. 1918) Olive Mary (-1943), of the Ceylon Civil Service, dau. of J. R. Innes, C.M.G.
His father was Rev. Andrew Caldecott (1852-1936), of Hardwicke, 10, Tennyson Road, Worthing, Sussex, educ. Merton Coll., Oxon. (B.A. 1876, M.A. 1879), Wells Theological Coll. (1882), rector of West Chiltington, Sussex 1898-, vicar of Eridge Green, Sussex 1891-8, curate of Boxley, Kent 1883-91, who m. 1883 Isobel Mary, dau. of Rev. Stenning Johnson, rector of Eastergate, Sussex.
Rev. A. Caldecott eldest s. of ANOTHER Andrew Caldecott (1828-1894), of Highcroft, Husbands Bosworth, Leics., formerly of Pishobury Park, Sawbridgeworth, Herts., formerly of Woodford Road, Forest Gate, E.7., landowner, merchant (inc. cotton) 'in Manchester trade', J.P., by his wife Eliza (1831-), dau. of William Charley, of Seymour Hill, Dunmurry, County Antrim (and apparently also of Derriaghy, County Antrim), chairman, J. & W. Charley & Co., linen manufacturers, and a founder of the Northern Banking Co.
The third son of Andrew Caldecott (1828-1894), Leslie Caldecott (1870-1946), of Boxley Abbey, Maidstone, Kent, was a brewer and company director; he married in 1897 Eleanor Mary, dau. of John Locke Stratton, of Turweston House, Turweston, Brackley, Bucks., J.P. [that family treated in BLG 1921], by his wife Mary (1838-1894), dau. of William Willes (1802-1865), of Astrop House, Northants., J.P., D.L., High Sheriff of Northants. 1837 [Willes formerly of Newbold Comyn in BLG 1969] by his wife Sophia (-1896), dau. of William Ralph Cartwright, of Aynhoe, M.P. for Northants. [Cartwright of Aynhoe in BLG 1952]
Leslie Caldecott's sister Ethel Constance (1862-) m. 1883, Edmund Ethelston (1858-1922), of Hinton Hall, Whitchurch, Salop., s. of Robert Peel Ethelston, of Hinton Hall [Ethelston formerly of Hinton Hall BLG 1972]; their sister Mabel Rose (1864-1952) m. 1891, Sir James Walter Turing, 9th Bt, s. of Sir Robert Fraser Turing, 8th Bt; their sons were the 10th and 11th Baronets, dying s.p.; the title was then inherited by a cousin, the 12th Baronet being nephew of the famous Alan Turing.
Andrew Caldecott (1828-1894) eldest s. of Andrew Caldecott (no surprises there at this point, surely...) 'Esq.', apparently at least sometime of London, that being where his son was born. Second son Edwin (1829-1892) was in business with his brother, and at the time of his death was of Upperton Farm House, Upperton, Eastbourne, Sussex.
There were numerous daughters I didn't research further, nor did I follow every branch to the present day, so there may well potentially be a good number of other connections with the families in which this group is interested.