Her Royal Spyness

Summary:

London 1932. Narrator Lady Victoria Georgiana Charlotte Eugenie, 34th in line for the throne, is flat broke. She bolted from Scotland — and engagement to Fishface (Prince Stiegfriend) — for London, where she has:

a) built a fire in the hearth
b) fallen for an absolutely unsuitable Irish peer
c) made a few quid housekeeping incognita, and
d) been summoned by the Queen to spy on her playboy son

When an arrogant Frenchman trying to swipe our family estate winds up dead in my bathtub, how can I clear my very long family name?