When Captain Potts pins the chart to the training progress board, the board has the intake as No.29 but when the prize giving is announced near the end of the film it is announced as the prize giving for the 60th intake
When Sgt Grimshawe throws the rifle to Strong, during Bayonet drill, the rifle is caught by Strong the opposite way around.
When Charles Hawtrey swings on the rope to cross the ditch he lets go of it. In the next frame it's back in his hand and he passes it to the sergeant.
During all the parades and square bashing the squad were not sized correctly for marching in a squad. The tallest should be at each end and then gradually decreasing in height until the smallest are in the centre. You can see this at the end where all the other squads were all correctly sized for the Pass out parade.
The recruits' tunics says DRAGONS. It should be DRAGOONS.
Most of the actors playing recruits are clearly too old to be doing National Service- it was for young men aged between 17 and 21, but Kenneth Williams, Kenneth Connor and Charles Hawtrey were 32, 39 and 43 during filming.
When written, the sergeant's name is shown to be Grimshawe - except on the training results board in Captain Potts' office, where it is Grimshaw.
When the platoon march off on the last day, the Sergeant and Corporal run to catch up with them. Then the Sergeant starts calling to step with left left left and the right feet are hitting the ground.
When Miles Heywood climbs down from the army lorry Big Ada II, the reflection of the mic boom can be seen in the cab door.
When Strong comes out from the quartermasters, he asks for help from a corporal. This is a training camp and the corporal's stripes are not sewn down.
In the first few seconds of the movie, just after Bob Monkhouse and Shirley Eaton get married, as Shirley tries to climb into the back of the taxi she clearly trips and lands flat on her face on the back seat.
This is in long shot and was plainly not deliberate.