Research notes
Publicly listed in the Team Members section of the FIA Formula 2 official team page. He has worked as an F2 racing mechanic at Virtuosi (later renamed Invicta) since August 2015, and is the Number Two Mechanic confirmed by FIA F2 official reports, working long-term alongside Number One Mechanic Rory Brodie, respectively responsible for the front and rear of the car, assisting the Number One Mechanic with car decisions and preparation work. LinkedIn shows Troy Cassidy as a racing mechanic at Virtuosi Racing, located in the Greater Norwich area (Norfolk, where Invicta/Virtuosi is headquartered), from August 2015 to present;
an FIA F2 official article also confirms Troy Cassidy as the Number Two Mechanic for Invicta (Bortoleto's car). The two sources match closely.