Legend has it that this prank was the Oliver Twins' revenge for Sinclair User giving the first game a bad review. They gave the game 9/10 and the reviewer said nice things - only concluding that Firelord was his choice for "the Ultimate Cartoon Adventure" - Codemasters were given to hyperbole about their own games even in the early days. Maybe Sinclair User were particularly harsh on other Codemasters games in comparison to Crash and Your Sinclair?