Henry Friedrich Everhard (I've also seen 'Frederick Everard'- probably anglicisation on his part or someone else's) von Westenholz was married (1stly- 1941, div. 1968 [his second wife- m. 1969- was Flora Evelyn Innes Stuart, formerly wife of the M.P. Sir John Anthony Langford-Holt]) to Marguerite Gordon, dau. of Capt. Gordon Stewart Ness, of the Royal Scots Fusiliers, a Lloyd's underwriter; his father was Patrick Ness, of Braco Castle, Perthshire, which seemed initially promising (i.e. indicative of a gentry background) but, at least based on what little I could find, turned out not to be. At any rate, Captain Ness's son, Major Anthony Patrick Ness, married as her second husband Princess Frederick of Russia, née Lady Brigid Guinness, dau. of the 2nd Earl of Iveagh.
I took a look at the Maudes just in case there was any connection to Angus Maude, a life peer but I thought of some notable ancestry (I might be wrong, however)- unfortunately nothing came of that either, as Group-Capt. Christopher Edward Maude, R.A.F. was son of a solicitor at Sevenoaks and Hampstead, whose father was a Yorkshireman. One point of minor note is that C. E. Maude's wife was, it seems, Ruth Anne SandwiTh, daughter of Fleming Mant Sandwith (son of Colonel John William Fleming Sandwith, of Bombay) by his wife Gladys Frances May (presumably a cousin- haven't had time to check this yet), dau. of Humphrey Sandwith ('IV'), an Army physician and writer- also Governor of Mauritius- of a somewhat prominent Wesleyan family.
Nothing terribly useful, I'm afraid, but a few notes nonetheless!