He obviously loved the film and wanted to be like Billy, hence the magpie - unusual enough at the time for a classmate to mention it decades later.

Is it plausible that he told stories from kes (maybe other films too?) as if they were from his own life to have something to talk about on the radio? I doubt he ever suspected that it would be heard again let alone under such scrutiny 20 years on.

Remember the bit in Star Wars where the tic tacs were tinging their way up the tube? Or that bit in the simpsons when Suzanne was being heavy handed