He was a hero alright, but he was also apparently an exemplary soldier, not the malingering n’er do well portrayed in the film. Presumably the producers thought that would be too boring and wanted a rogue instead.
Apparently, Colour-Sergeant Frank Bourne, who is portrayed as a man well into middle age in the film, was only in his early 20s at the time of the battle, and was the last veteran of that battle to die. Coincidently, he died on the 8th of May 1945 aged 91, on VE Day...
I think James Booth is wonderful as is the characterization. I’m sorry the family was upset but seeing the slothful Hicks finally moved to action and heroics is what filmmaking is all about! And the Color Sergeant always reminds me a little of Arthur Treacher’s performances in earlier films.