Only thing I can think of is it’s maybe mentioned in the original manuscript but was cut from the published text. Otherwise I wouldn’t know.
Mind you, for the longest time Fleming didn’t mention SIS/MI6. To the best of my knowledge he never mentioned SOE, Enigma/Bletchley Park/GC&CS for very practical reasons*: he was bound by the Official Secrets Act to keep his trap shut.
Therefore it seems likely Fleming might have had second thoughts - or have received a tap on the shoulder - about mentioning a probably top secret installation less than ten years after the war. An installation that possibly was kept secret until the 70s or even later.
*Likewise did many other spy writers who were in some way or form involved in wartime intelligence. They came up with euphemisms and nicknames like ‘Bureau’ ‘Department’ ‘Circus’ and the like. And some of the wartime spies and commandos were extremely cross with Fleming, the bureaucrat, for cashing in on their experiences - while they themselves weren’t allowed to talk about it.