The pub, at which the two soldiers stayed prior to stealing a boat for their journey to France, had all it's lights blazing at night, even though the whole country was under blackout regulations throughout the war.
The British locomotive seen taking the two men to Plymouth (preserved West Country Class - Blackmore Vale) was not built until 1946.
During the attack on the German Listening Post the Sergeant climbs over a container to get onto the roof. This type of container wasn't invented until 20 years later in the 1960s.