Start with high-confidence 20th century britain books, then narrow by subgenre or adjacent topics.
The Hotel on Place Vendome
Tilar J. Mazzeo
The Scapegoat
Lucy Hughes-Hallett, Harper
Lady in Waiting
Anne Glenconner, Grand Central Publishing
The Splendid and the Vile
John Lee, Erik Larson
Every Valley
Charles King
Advance Britannia
Alan Allport
The Pity of War
Niall Ferguson, Graeme Malcolm
Victorious Century
David Cannadine, Kris Dyer
The Prince and the Plunder
Andrew Heavens
Lady Almina and the Real Downton Abbey
Countess of Fiona Carnarvon, Fiona Carnarvon
Eighteen
Alice Loxton
Churchill
Andrew Roberts, Stephen Thorne
Lusitania
Greg King, Penny Wilson
The Battle of Versailles
Robin Givhan
Dominion
Peter Ackroyd
Geography Is Destiny
Ian Morris
The Smart Words and Wicked Wit of Winston Churchill
Max Morris
Some Do Not...
Ford Madox Ford
