Plot holes: When the buses leave St Trinian's, the leading bus knocks down the arch over the gateway. It can hardly have come in this way without knocking it down. Nor is it likely to have increased in height as it leaves laden with the girls and their equipment.
Continuity: The first shot of the tow-rope between the buses shows two pieces of cloth/ flags attached to it. Subsequent shots show only one piece of cloth.
Continuity: In The Belles of St. Trinian's (1954), the headmistress is Miss Millicent Fritton, whereas in this film her name is Miss Amelia Fritton, despite being the same character and being played by the same actor.