How long have I been here? That time, plus about three weeks.
Patrol schedules, a layout of the area surrounding, a good look at the vehicles this lot drives. Unsurprisingly, once you had taken Old Blighty they upped their security, but some time spent in close surveillance should be able to overcome it quite handily.
Additionally, I made friends with the baker who provides bread to the canteen. He isn't proud of providing bread to Nazis, but a man's got to make a living, after all. Given that same time observing the building, one should be able to convince Michel to hire a few new delivery lads and ladies.