The stories they were based on...
Although I appreciate that the episodes were based on a number of different general influences, there do seem to be some main sources for some of them...
* Whinfrey is a parody of The Riddle of the Sands, and to a lesser extent John Buchan.
* Schooldays is a parody of Tom Brown's Schooldays.
* Eric Olthwaite is partly a parody of Bonnie and Clyde.
* Curse of the Claw is a parody of the Monkey's Paw.
* Stalag Luft is a parody of the Great Escape.
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It's not "sci-fi", it's SF!