Is this an ad for Leonardo? 'Greg would only speak to BBC under a pseudonym'...really?
There are many professional, military-or-adjacent red team folks who'd gladly speak to BBC with real names and credentials...
The irrational conspiracy part of my brain thinks Greg is probably undercover MI6.
This would actually be somewhat smart. MI6 could "private label" their pentesting. Their agents get free (actually negative cost) real-world training. You can pick the client list to include both local industries that you would prefer be secure, and potential adversaries that you can infiltrate for "free".
Best covert is overt.
He's a triple agent in his spare time.
He breaks into his office and writes himself up for his own poor security.
That'd be an interesting job interview technique, albeit probably not a good technique: prospective clients are refused at the door and have to finagle their way into the conference room.
I wouldn't underestimate how much of the British establishment is in some way connected to the SIS. there's a reason the Post Office wasn't sold off with Royal Mail
Given they're supposed to show up at top-secret bases and find a way in, they probably don't want their real names and photos to be a Google search away for blue teams to recognize on sight.