Continuity mistake: In War Dance (4-2) the verger Mr. Yateman's wife's Christian name is Anthea. In Everybody's Trucking (8-1) it is Beryl, and in Knights of Madness (10-3) she is called Tracy.
Other mistake: The Church Hall got through an impossibly large number of different pianos, especially considering the fact that there was a war on.
Continuity mistake: (Colour episodes only) In the section of the closing credits that features the main cast members marching, the sky colour and positions of the shadows on the ground change depending on the actor being featured at the time (the sky is blue when Arthur Lowe, John Laurie and Ian Lavender are seen, but it is grey when John Le Mesurier, Clive Dunn, James Beck and Arnold Ridley feature). This is more obvious on episodes that have had colour restoration undertaken.
Visible crew/equipment: "Resisting the aggressor down the ages" (Christmas night with the stars special episode) Just after Jones bangs the gong at the wrong time and says "that was a mistake, I'm sorry" there is a boom mike shadow on Mainwaring's union jack waistcoat.
The Armoured Might of Lance Corporal Jones - S3-E1
Visible crew/equipment: As Hodges is gathering a crowd together to witness the demonstration of how the van can be used as an ambulance, a boom mike can be seen briefly at the top of the screen.
Continuity mistake: The platoon's rifles have no fore sight at various times in this episode, at other times they are fitted. Most noticeable on the railway platform and the march to camp (missing), but when they arrive at the camp, all the fore sights are on. They are missing during the outdoor training scenes - and they are missing from the credits at the end of every episode when the platoon members are shown in close up (these shots were from this episode). (00:09:00)
Other mistake: When the train stops Godfrey gets off to relieve himself but when he is climbing back in to the carriage the train appears to be already moving at speed because the background projection started moving too early.
Other mistake: Walker is attempting to steal items from the farm but appears on the training activity with the other troops at the same time.
Continuity mistake: The Verger Mr Yeatman's first name is Maurice, but in this episode it is Henry.
Revealing mistake: When Frazer is attempting to get the chocolate out of the crane machine, he tells Mainwaring to keep quiet. When he does this, he takes his hands of the machine, and it picks up the chocolate on its own, without anyone controlling it.
Visible crew/equipment: When Pike returns to the arcade to tell the platoon that he has lost the boat you can see the shadow of the boom mike in Walkers face.
Visible crew/equipment: Towards the end of the episode where Godfrey goes back into the smoke filled hut to rescue Captain Mainwaring, the shadow of the camera is visible on the hut.
Don't Forget the Diver - S4-E2
Factual error: While Capt. Square is looking through his binoculars at what he thinks is Mainwaring's platoon marching with their rifles, a 1960's Bedford lorry drives past on the road behind them.
Factual error: In several scenes during the cricket match while the Walmington platoon are bowling/fielding, cars can be seen on the road behind the cricket ground that were made well after the 1940s.
Battle of the Giants! - S4-E14
Factual error: When Mainwaring is driving the van and Jones is in the back suffering from malaria, just after Pike shouts out that Jones has changed colour, if you look out the side window you can see a triangular road sign. These did not come into use until the 1960s.
Battle of the Giants! - S4-E14
Visible crew/equipment: When Hodges tells Mainwaring to pull over when he is driving Jones' van you can see crew members reflected in the left hand side of the van's windscreen.
Battle of the Giants! - S4-E14
Revealing mistake: Just before the two vans drive round in circles, when Mainwaring has trouble with the gearbox, the shot from inside the van shows a house through the driver's window. But in the exterior shots there are no buildings around, just trees.
Battle of the Giants! - S4-E14
Continuity mistake: When the Walmington platoon stop their van to open the gate to let the sheep out in attempt to hold up the Eastgate platoons van the Eastgate van drives through the gate into the field with Hodges on his motorbike following, but when the camera cuts back to the road the Eastgate van and the motorbike are on the road behind Walmington's van, the Eastgate van and the motorbike are next seen coming out of the field further up the road.
Battle of the Giants! - S4-E14
Continuity mistake: When Mainwaring and Square, driving the vans, are trying to push each others' van off the bridge, Hodges parks his motorbike at the end of the bridge behind the eastgate platoon's van. In all the following shots Hodges' motor bike has disappeared.
Battle of the Giants! - S4-E14
Visible crew/equipment: Early in this episode, when Mainwaring and Wilson are in the office, there is a knock on the door. Mainwaring tells Wilson to answer the door. As Wilson makes his way to the door, there is a shadow of the overhead mic on the wall behind him.
Answer: The show is a comedy, this was played for comedic effect and to show that in times of extreme fear, in this case about to be crushed by a steam train, the men had an adrenaline surge strong enough to pedal fast enough.