Upper-class pronunciations are all over the place. The Cholmondeleys are pronounced the CHUM-leys. The Earl of Harewood is the Earl of HAR-wood. The Beaulieux are the BEW-leys. In accordance with the convention that French words should be pronounced as far away from the actual French style as humanly possible, just to show those French people who’s boss, Beauchamp Place, a street in Knightsbridge, BEACH-um Place. Jacques, in Shakespeare: JAKE-weeze. Your valet is your VAL-let. Madame Tussaud’s wax museum? To some Brits it’s MA-dam TOO-sod’s).
That is from Sarah Lyall’s not fully analytical but often quite amusing The Anglo Files: A Field Guide to the British.
Here is a picture of Thomas Cholmondeley [CHUM-ley], and with this caption: "The trial has opened in Nairobi of an aristocrat
accused of murdering a black Kenyan man he suspected of poaching on his
family’s 100,000-acre estate." The case, the second of its kind brought against Thomas, remains pending. Here is more information. Here is his girlfriend.