I will look deeper, but at the moment I am riveted by the obituaric notes and other small references, all of which seem like iceberg-tips. For instance, here is another NY Times headline (December 18, 1915):
EARL DE LA WARR DIES AT MESSINA; Head of English Family, After One of Whose Ancestors State of Delaware Was Named. STRICKEN IN DARDANELLES Son of the Late Lord Sackville Was a Boer War Veteran, and Twice Married and Twice Divorced.Or, and sorry to jump back in time, what about the 6th Earl, Major-General Charles Richard Sackville-West? He had a glittering career in India and the Crimea, among others. In 1873, four years after acceding to the title, he drowned himself in the River Cam. I do not know why. He was 57 and without issue.