The spy wore silk - Andrea Pickens

By all outward appearances, Mrs Merlin's Academy for Select Young ladies is indistinguishable from other English boarding schools. But the Academy's students are all orphans - they've been plucked from the streets for their toughness and intelligence, and with training in manners, martial arts, swordsmanship and deportment, they are transformed into English spies. One such woman, siena, is chosen for a highly dangerous job: to infiltrate an elite circle of British aristocrats and uncover which one is selling state secrets.
Forced to resign his army commission, Adrian Henning, the Earl of Kirtland, feels joy only in the company of books. But his weekly meeting with The Gilded Page, a very exclusive club of book connoisseurs, is ruined by the sudden appearance of London's newest and most notorious courtesan, the Golden Dove.
The Golden Dove is, of course, Siena, and the reclusive Earl of Kirtland proves to be most difficult to investigate. As they each try to decipher what game the other is playing, the plot thickens, and they must work together to bring down the real enemy.