In Mrs. Dalloway, Clarissa wonders if Hurlingham might be the cause of the traffic. Hurlingham is a polo ground outside London. The Woolf's went to see the polo there in May of 1923, when she was returning, in earnest, to drafting the novel. In a letter, Woolf writes:
"We’ve just been to see the Polo at Hurlingham, and my wits are gone. How I wish I were the Duke of Peneranda and could play polo! And what d’you think they’re like to talk to?—the D. of Peneranda, the Marquis of Cholmondeley? Imagine their conversation” (L 3.41; 21 May 1923; to Molly MacCarthy)
Wikipedia tells me, after some labor, that "The Duke of Peñaranda de Duero was a Gentilhombre de Camara (Gentleman of the Household) to King Alfonso XIII of Spain. At the1920 Summer Olympics he and his brother were on the Spanish polo team, winning the silver medal."