In the film, the defendants are allowed to gather in a common room until lights out to socialize and meet with their lawyer and other visitors. In reality, there were six defendants in total, including Captain Taylor, who were held in strict solitary confinement from their arrest through sentencing and were not allowed to communicate with each other at all.
In the closeup of a soldier's finger pulling the trigger of his Enfield rifle during Lt Morant's explanation of "Rule 303" to the court, the rifle stays absolutely still when the shot goes off. In actuality, a high-powered rifle like the .303-caliber Enfield would "jump" noticeably at the instant of firing.
The band plays an excerpt from Franz Lehár's The Merry Widow, which premiered three years after the trial took place.
During the Morant trial, a military band is heard playing Edward Elgar's "Pomp and Circumstance March No. 1." The march was premiered in England in October 1901, and it is very unlikely that an arrangement for military band was available less than two months later when the trial took place. It wasn't until later in 1902 that the words "Land of Hope and Glory" became permanently wedded to the tune.
When the Boer asks the black guide in Afrikaans "Het jy die regte kennis?" this is an incorrect way of putting it as the sentence literally means "Do you have the right knowledge?" The correct question should have been "Het jy die regte inligting?" meaning "Do you have the right information?"