I need help finding a short story/excerpt I remember reading in a "best of sci-fi year?" omnibus
I remember the setting being about a future great game between great powers involving Great Britain, which the main character is a citizen and soldier (mention of a "dragoons?" uniform) of. He visits a embassy on a mission and sees a girl that is a special type of person that can lock information in their subconscious. That's vaguely what I remember.