And the friend has outlined the range of artistic interests Scott might have shown the world if he hadn't died in 1980, just before the band went global with replacement Brian Johnson and classic album Back In Black.

Peter Head's memories are among those set to fuel documentary movie Looking For Bon, planned for release next year - the 35th anniversary of Scott's death. It's to be followed by a second film that will focus on his time with AC/DC.

Head, who worked with him in Mount Lofty Rangers and Headband, tells Billboard: "When I first met him in Adelaide he was with Fraternity, and the sort of music they play, you'd only call progressive rock. It was highly artistic - they wouldn't use Bon's lyrics, but his voice was fantastic. It was far more musical than AC/DC, but AC/DC were more entertaining on a gut level."

He's kept some of Scott's letters, in which he wrote of the struggle to capture general audiences with Fraternity's prog rock - although the band secured the interest of several big names from the art world.