Wow! Thanks, Retro! I appreciate all your efforts here in finding the CD
According to Lomax, there's only one track taken from the Bruton library, the rest of the tunes were produced specifically for the project (originally without the vocals, which were reluctantly added later, according to the story). He writes (p. 426):
"The soundtrack heard in the film included a Bruton library title—Francis Monkman's The Dawn of an Era (from BRI 4 Energism)—whereas the soundtrack album, issued on the Pye label, was devoted entirely to the Bruton Band's score…"
The Monkman track appears in this scene from the film: