Hopgood's story was originally half comic, half serious, and Burstall originally envisioned it as a 20-minute section of a multi story picture. However he then decided to make the story strictly comic and expand it to feature length. Burstall says he rewrote much of Hopgood's script, adding many chases and the water bed sequence, and turning McBurney figure into a sex maniac. The original script played more emphasis on the relationship between Alvin and his virginal girlfriend but this was cut in the final film.