Sometimes an idea is so ridiculous, it works because the viewer is so distracted by its absurdity. What if we could make an episode of the familiar parade then outing, but with the platoon in German uniforms?
Ian Lavender comes into his own again after his famous scene in The Deadly Attachment - given a uniform equivalent in seniority to Mainwaring, Pike is determined to embrace method acting as a German officer set on world domination.
The big plot hole is why on Earth the rest of the men - who normally have functioning brain cells - think they can go into the bar without explaining what they're doing? After all, it's not the training film that's supposed to be the secret part. The only explanation is that they're going delirious from the lack of water and oxygen.
It's a fascinating short story in itself of making the viewer imagine a genuinely interesting possibility of a wartime incident. Granted, there have been church bells incidents in Dad's Army before, but this time we see the false alarm - and its consequences - spread beyond the platoon and allows room for reflection after.
A certain amount of suspension of disbelief around poor communication has to be shown in any sitcom - I'll certainly accept it in return for possibly the best episode of Dad's Army.