This is very much par for the course with the BBC. They decided to rewrite the main character in "This Is Going To Hurt" as homosexual even though the source material is autobiographical and the author is a heterosexual male. Made no difference to the story.
Nothing wrong with being gay, straight, bi, whatever.
Equally nothing in any of the historical stuff I've read to suggest Paddy Mayne was homosexual. But then again, why would there be? What does that add to the history of the birth of the SAS and their activities in WW2? What does it detract? Much of the source materials were written in an era where people often kept this aspect of their lives a very closely-guarded secret. Some of the more recent biographies of Mayne may offer some answers there - I haven't read all of them.
The actor playing Mayne is doing a cracking job though. The scenes were he was emotionally in turmoil over the death of his implied partner were really impactful and provided a plausible context for his violent and impulsive behaviour.
