Anyone remember the follow-up book "Billy Liar on the Moon", if I remember rightly?

I always thought that the Jam raririty "Liza Radley" was inspired by Liar's girlfriend in the film.  Sadly, I read recently it was about being in love with the local hooker.  Much preferred my interpretation of the girl who was leaving the small town for a sophisticated destiny in London and sadly, you ain't going with her.