Alex Cruz has nobody responsible for IT reporting to him.
I'm not sure that's 100% accurate? I admit I don't know IAG's structure.
However, even with a shared Group IT, typically there's still a Head of IT responsible for each Line of Business (LOB). Sometimes even more than one (e.g., Heads of IT architecture, IT delivery, IT operations, etc.)
The Head of IT for the LOB would then have "matrix" reporting to both the Group IT Head (e.g., Bill Francis) and to the LOB Head (such as Alex Cruz) or an LOB CIO (if the Head of IT is not the CIO.)
It's not unusual for Group Heads to be a business exec, not a technical manager.