A minor addition: A. P. de Ritter, per
thepeerage.com (citing an e-mail from a Henrietta de Ritter; following details supplemented by other internet sources), s. of Lt-Col Ronald Birch de Ritter (1912-1955), R.A.S.C., of 23, Mount Hermon Road, Woking, Surrey (per probate record) and (m. 1940) Joan Talbot Coke (1918-1998; presumably a member of that family- later Coke-Steel- of Trusley, Derbys.? BFI has them (in hyphenated form) last in BLG 1972, and Google books shows the 1898 edition to include a John Talbot Coke of Trusley, so logically they're in intervening volumes also; I'll check 1952 tomorrow and update if relevant)
R. B. de Ritter's birth record gives mother 'Birch'; 1912 marriage of Ernest G(eorge per probate record) de Ritter (a death record indicates 1875-1955), of 11, Curzon Road, Birkenhead, Cheshire, and Edith V(ictoria per husband's probate record). Birch. No evident birth record for Ernest (an Ernest Edward de Ritter born 1876 d. 1954, clearly another individual entirely); possibly of foreign origin?