When Geoff is driving in the rain, the car is actually being pushed along because Reece Shearsmith cannot drive.
The League got the idea for the film when they were trying to write another film called "The King's Evil", but they were all suffering from writer's block. So they decided to make a film where the characters from the show discover that they're just characters in a TV program, and their world is being destroyed because the League have quit writing about Royston Vasey.
Filming took place in Dublin, Ireland as it would cost far less (due to tax breaks) than in England, where the three TV Series were filmed.
The actors expressed a desire for Dr. Pea's laboratory to be turned into an Aurora-style model kit as merchandise for the film.
When the writers are taken through the portal into Royston Vasey, Bernice says "the League of Gentlemen...... extraordinary" in a clear nod to A Liga Extraordinária (2003)