Plot hole: When Miss Price, Professor Browne and the children return from their magical journey to the island of Naboombu and realize they no longer have the Star of Astroroth pendant, Miss Price says, "I should have known it would be quite impossible to take an object from one world into another." Yet, they had no problem taking themselves, the bed, blankets and pillows from one world into another.
Continuity mistake: When the Germans are in Ms. Price's house, the German officer quickly hands a paper to a soldier who comes running. Watch how the soldier, in his hurry, misses by far and grabs the officer's arm at elbow level. In the close-up he corrects the position and is now grabbing the paper.