"But Miss Garnet, who was looking up, had caught the benevolent gaze of an angel. He was standing with a protective arm around what appeared to be a small boy carrying a large fish."

 This is the Angel Raphael and the boy is Tobias, whose story begins on page 70 of the novel and runs alongside Miss Garnet's own. The statue stands above the door of the Chiesa dell'Angelo Raffaele on the waterfront. In the first picture below (left) you can see the quayside where Miss Garnet alighted from the water-taxi.

The church is marked '2' on the map at the back of the book (Afterword p. 7).       

Chiesa dell'Angelo Raffaele with waterfront
Public DomainChiesa dell'Angelo Raffaele with waterfront - Credit: wms

 

 

 

Raphael andTobias
Public DomainRaphael andTobias - Credit: wms