Some details of the Marriotts:
Ian Arthur Marriott was of Flat 2, Highfield House, Lymington, Hants., formerly of Newnham Hall (the Marriott family is connected with a Newnham House; either this is an error in the source I used for this part, or a separate dwelling so named in reference to Newnham House, of which more below), Newnham, Northants., Lt-Col Royal Engineers.
His father was Hugh Frederick Marriott (1869-1949) of Newnham House [possibly also of The Grove], Newnham, nr Daventry, Northants., and 16, Aberdeen Court, Maida Vale, a mining engineer. He married in 1909 (possibly later div.?) Eveline Annie (1883-), dau. of Charles Penton Kerr (1855-1895), of Camberwell. They also had two daughters, Daphne and Sylvia.
H. F. Marriott was s. of Arthur William Marriott (1839-1916), of The Manor House, Perry Hill, Lewisham, and Newnham House (details as above), ship insurance broker (and Lloyd's broker), formerly in business with his father as general merchant (23, Rood Lane, City of London). He m. 1863, Elizabeth (1841-), dau. of - Barnes, of Fenchurch Street. Their sons were:
i) Percy Arthur Richard Marriott (1864-1907), educ. Cavendish Coll., Cantab. (B.A. 1888, M.A. 1892), canon and precentor, St George's Cathedral, Jerusalem 1905-7, rector, Redhill, Hants. 1898-1905, curate, St Bartholomew's, Southsea 1895-8, curate, St John's, Clay Hill, Enfield, Middx. 1893-5, curate, Bierley, Yorks. 1889-92. He drowned whilst swimming at Palestine.
ii) Thomas Edgar Marriott (1865-1952) of The Nuttery (part of The Grove estate; details to follow), Newnham, formerly of Newnham House (temp. 1899). estate agent
iii) Hugh Frederick Marriott (as above)
iv) Charles Percival Scott Marriott (1872-1948) of Daventry
v) Oswald Marriott (1874-1953) of Linacre House, Rockshaw Road, Merstham, Surrey and of Revenue House, 7 Poultry, E.C.2, M.D. (Lond.), M.R.C.P., Fellow (1908-), Royal Society of Tropical Medicine and Hygiene (the source gives as follows: 'Loc. Sec. 1909-21. Aud. Com. 1930-31. C. 1931-47. T. 1935-47.' - I wasn't too sure what these acronyms meant), lecturer on pharmacology and therapeutics, University of Hong Kong (temp. 1922)
i) Maud E. Marriott (1866-)
ii) Ethel Constance Marriott (1867-)
A. W. Marriott was s. of Thomas James Marriott (1794-1880), of The Manor House, Perry Hill, general merchant (23, Rood Lane, City of London), who m. 1835, Ellen Mary (1811-), dau. of Abraham Mann, of Clapham, Surrey. They had four sons (Arthur William being the second) and three daughters.
Thomas Marriott is stated in the census to have been born in Northamptonshire; this fits with the family's possession of an estate there, the details of which are not entirely clear. I found early-nineteenth-century references to the Marriotts of Newnham House; whether or not Ian Marriott changed its name to 'Hall', or lived in another house is not clear. The Marriotts apparently, in the grounds of 'The Grove', which they owned, established a nuttery, the hazelnuts from which were apparently (possibly still are?) taken to Covent Garden and sold. What exactly this means with regard to the residence of Thomas Edgar Marriott (see above) is unclear. A Wikipedia article on Newnham, Northamptonshire- which appears to get this part of its contents from
http://www.treganservices.co.uk/Newnham.PC/history.html, evidently a local website- states as follows:
'Newnham Hall dates from 1820 and is set in 120 acres (49 ha) of Northamptonshire Parkland. Newnham Hall was the home of the former Lord Lieutenant of Northamptonshire, Lieutenant Colonel John Walkelyne Chandos-Pole OBE, who died in 1993. Another fine residence is The Grove. Located in the grounds of The Grove, which was owned by the Marriott Family, is the Nuttery which is the site of a hazel orchard. The Nuttery was planted by the Marriotts of Newnham House.'
This clearly indicates the Marriotts to have been of both Newnham House and The Grove, but seems to draw a distinction between the House and the Hall. Unfamiliar as I am with Newnham (and Northamptonshire in general), I'm afraid the details escape me!