Cottage to Let (1941)

In this war-time mystery from England (it was called Bombsight Stolen in America) a nest of German spies infiltrate a country estate in Scotland. Other guests and inhabitants include a precocious evacuee child who fancies himself Sherlock Holmes, a Scotland Yard detective masquerading as a butler, and a couple of scientists working on an innovative new bombsight. There are a few too many characters in the mix but it's efficient well-acted escapism, just not particularly memorable.