I've come to the spy part, but ... the premise is really preposterous.
To be honest, this book really is not great so far.
I like that it is set in Trieste against the back-drop of Marshall Tito, the Cold War, and the rebuilding of an Italian society after WWII, but the actual characters and stories and in particular the espionage part involving an imagined Cary Grant are ... best described as what I would expect 5 teenage boys to come up with while pretending to be cool and sophisticated.
There is a lot of pretense in this book, made worse by a focus on descriptions of what people are wearing and whether their choice of wardrobe is elegant or even well chosen.
I'm not sure I will finish this one.