National composition of the soldiers of the 24th Regiment of Foot

In the film the regiment is called the South Wales Borderers. The unit was not, in fact, called that until two years after the battle, even though the regiment had been based at Brecon in South Wales since 1873).
While most of the men of the 1st Battalion, 24th Regiment of Foot (1/24) were recruited from the industrial towns and agricultural classes of England, principally from Birmingham and adjacent southwest counties, only 10 soldiers of the 1/24 that fought in the battle were Welsh. Many of the soldiers of the junior battalion, the 2/24, were Welshmen. Of the 122 soldiers of the 24th Regiment present at the Battle of Rorke's Drift, 49 are known to have been of English nationality, 32 were Welsh, 16 were Irish, one was a Scot, and three were born overseas. The nationalities of the remaining 21 are unknown.