DR TOMovOZ - this is what Jules Nurrish the writer of NO ORDINARY JOE says:
I did not use actual pieces from the published Diaries, instead opting to write the narrative myself, in the often outrageous style of Orton. It was challenging to try and successfully make the main character believable, while creating a voiceover narrative that belonged to a semi-fictional Orton.
So perhaps he wrote that line himself.