More likely a reference to his trip(s) to Prague actually ¹.

That and the fact Stephen’s a dodgy geezer to begin with ² — if he were a cinematic/literary character, he’d be Harry Lime (just ask Gutbloom).

‎

But what would I know? … I’m only the author, after all … You’re probably right … I’m probably just spreading unfounded gossip.

Otoh, he is adopted and nobody loves him, so … either way around … no harm, no foul, really.

‎

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¹ You have noticed me reference Funeral In Berlin, The Man From U.N.C.L.E. and suchlike in the past, yes? You appreciate why his trip(s) to Prague might be fruitful material for a Cold War plot reference, right?

² https://whereangelsfeartotread.medium.com/pssst-9fd40af8dc51