The telephone box only has glass installed on two sides. Mainwaring slightly puts his gloved hand through the lattice on the door, revealing this.
When Mrs Fox hands Walker a 'half crown' she gives him a washer with a hole in it.
"I've never heard you swear before, sir," says Wilson after Mainwaring bridles at the Germans' "bloody cheek." But he'd been shocked in the first season edition "The Showing Up of Corporal Jones" when the Captain referred to Major Regan as a "rotten bastard."