And the point goes to Dowdeswell for the correct answer.
This puzzle raises a technical question. There is a very good chance, that only one F&M Vulca S exists, and it was later modified to become the only Aquila Italiana Diva GT. Does this mean this puzzle should be merged with Carnut's Vulca S puzzle? Two body panels were modified, as F&M badges were removed, along with the indents they sat in on the front and rear of the car. The Aquila Italiana web site shows bare-metal photos of their car being built, and you can see the original F&M indent on the rear of the car.