As far as using non-British weapons, I believe you don’t usually use weapons from your own country when you’re a secret agent overseas. It’s easier to deny working for your country and harder to be identified as being from a certain country. I think this is actual spy craft SOP. SOG groups didn’t even carry US weapons early in the Vietnam war so it would be harder for people to say we were where we weren’t supposed to be. Hence the Swedish K, Browning HP. Having a German gun is good for a British agent not trying to look like a British secret agent.
For a real secret agent, I would say G19 because it’s ubiquitous, reliable, reasonably compact, and good firepower. 9mm can be found most places. Second choice is S&W 642. Compact, reliable, light, no shell casings.
For James Bond character, the PPK isn’t a bad gun. .380 is ok for self defense when your not expecting a professional ambush. It’s compact. I like the manual safety for pocket use. It’s reasonably ubiquitous. In one movie I believe he used a Walther P5. I think he should have stayed with that because I think it’s cool.
Also, the new Bond movie sucked. Don’t see it.