I've been reading "The Making of the Atomic Bomb" by Richard Rhodes and came across a mention of private and semi-private meetings between Niels Bohr and FDR as well as Bohr & Churchill. At each meeting, he implored them to open limited atomic research findings to the world, as he and some of his contemporaries had been inspired by works like H. G. Wells's "The Open Conspiracy" which promoted worldwide scientific equality unbound by borders and politics.
Are there any indications that he got through to either of them at any point, or that either took this suggestion seriously?
There's no indication either of them even understood what he was arguing for, much less took it seriously. Churchill thought Bohr was essentially dangerous, and FDR's reaction was to see who he had talked to about this out of fear of it being a security breach.
It's not that either would have been totally dense about the possibility of international control. Truman managed to be somewhat convinced of its importance, by Vannevar Bush, and Churchill probably could have been convinced of it if it had been put in the right framing (preventing the USSR from succeeding).
But Bohr was an exceedingly bad person to try and introduce the idea to both of them. He had scientific stature, that's true. But he was notoriously incomprehensible — he mumbled, he agonized over wording, and he was entirely unconvincing on political matters. His approach to international control was fairly "naive" — while it would be very similar to that later proposed by Oppenheimer, Bush, and others, it lacked political savvy and policy framing. It was essentially an appeal to scientific openness, which was not going to be convincing on its own. Oppenheimer and Bush turned this into "inspection," which is not quite the same thing. Bush, as an aside, totally understood how politicians thought and was very able to convince them of a great many things. Oppenheimer could be very charming and sometimes very savvy about politics. Bohr was really neither of those things.
If someone more practical and compelling had introduced the idea, would they have been more interested? It's hard to say. But again, Bohr was really quite bad at it.