Most impressive military/inteligence background of the Bond filmmakers?
Many of those involved in making the Bond movies had military backgrounds, especially the early ones. A few had espionage experience too. I think we should include people working both behind and in front of the camera.
A note on Christoffer Lee: He claimed to or at least hinted at having experienced dramatic things behind the lines with SF units during WWII. Lee flew fighter planes, but had to transfer to RAF intelligence because of health issues. That's impressive in itself. But Lee left the impression he served behind enemy lines with elite units such as the SAS and SOE. I don't know about any independent sources (written reccords, people who served with him) who can confirm any of it, and some question if it really happened. It's up to you how much you chose to belive.