It's Not Cricket(1949)

Kicked out of Army Intelligence, a pair of upper class twits set up as private detectives. The result is refined English chaos. "This is the regettable story of two Drones who didn't even know their own Zones. It starts in Germany, gets nowhere and stops at nothing." Radford and Wayne, cashiered from the army when they let a captured Nazi escape, become private detectives who later get involved with the same German and a missing diamond ...