The plot revolves around the confusion of two map references, 937641 and 641937, the locations of an empty barn and a shooting target. Since the town of Walmington-upon-Sea, where Dad's Army is based, is supposed to be on the Kent coast, these translate to Ordnance Survey map references TV937641 and TV641937, both of which are in the English Channel.
There are many tire tracks in the grass along the side of the road during a couple of Godfrey's wild driving scenes indicating there were other previous runs before the final take.
Captain Mainwaring says he bought his greatcoat as the "really chilly weather" was about to come in. The foliage during the location shoot reveals that it was in fact spring.
To further the plot Jones' pencil has to break while he is taking a telephone message. He quite clearly stops writing and presses heavily on the pencil to achieve this.
The 25 pounders that fire on the barn have modern Flash Deflectors fitted on the ends of the barrels, all 25 pounders of the period just had plain ends
When Jones is towing Godfrey they pass a pattern of roadsign that didn't exist until 1964.
When Jones is walking away from the vehicles toward Godfrey to tell him about the map coordinates mistake, in the background there seems to be a person wearing a green shirt and black trousers standing behind the two cars.
The boom mic's shadow is clearly visible on the Church Hall wall as Jones prepares to kick in the office door.