One of the key elements in the plot was about Orton writing the script for a new Beatles movie, "Up Against It," which he fully expected them to reject because "the boys, in my script, have been caught in-flagrante, become involved in dubious political activity, dressed as women, committed murder, been put in prison and committed adultery." Paul, I believe, is on record as saying, they just didn't do it because they were worried fans would think they were gay. Probably a mistake on their parts, but then I haven't read the script. I'll have to hunt down a copy. I'd love to see somebody use the animation style from "Yellow Submarine" to a make a movie of it now.
But then I might just be thinking that because a Joe Orton version of Yellow Submarine sounds a bit like the book I'm trying to write.