But have we even looked for suitable evidence?

Who's "we"? You're the one making the argument, therefore it's up to you to prove Richard Maibaum had the kind of inside knowledge that would make him a whistle-blower.

Do we even know what sort of acquaintances the author had?

No, and that's precisely why your argument fails. We know what kind of acquaintances Ian Fleming had: his colleagues in the intelligence trade. The same argument will work for Maibaum if you can show that he had similar colleagues. But you can't simply co-opt the Fleming argument and make it work for Maibaum without establishing for Maibaum the things that make it work for Fleming.

Have you received a responce from Richard Maibaum?

Of course not. He died in the mid 1990s and I don't trust seances.

But I find it disappointing that you didn't seem interested in finding Maibaum's co-writer and trying to get the story from him. That's what I'm doing. That's what you should be doing.

I can't stress enough that if you want it to believed that Richard Maibaum had the same kind of intelligence contacts that Fleming had, it's your responsibility to prove it, not our responsibility to prove he did not. (In fact, it cannot be proved that he did not.)

Your unequivocal statement would seem to suggest so.

My statement was not unequivocal. It was qualified with "prima facie", meaning that I can accept it as plausible -- without examining additional evidence -- that Fleming had insider intelligence information. I know he worked in the intelligence trade and maintained his contacts there throughout his life. Since I have no such information for Maibaum I cannot accept it as plausible -- without additional evidence -- that he too was an intelligence insider. I know that Maibaum worked as a screenwriter. There is no natural connection between screenwriting and intelligence.

Far from being unequivocal, my statement correctly identified the difference between the insider argument applied to Fleming and the same argument aplied to Maibaum.

It now falls to you to prove the proposition that Richard Maibaum likely had, or actually had (not simply may have had) insider intelligence information that would have made him a genuine whistle-blower.