Don't Panic Chaps(1959)

During World War II, four British soldiers are commissioned to set up an observation post on a seemingly deserted island in the Mediterranean. However, while surveying the island, the Brits come across four German soldiers holed up in a monastery. The Brits and the Germans agree to a truce, sharing the monastery together until either the British or German troops arrive. But when a shipwrecked Slavic girl ends up on the island, a battle over her erupts amongst the men.