There are loads of good books on the Zulu War, and several not so good "popular" accounts. However, the film is a film; it is a dramatised interpretation of a real event. The bare bones of the story is true, but there are loads of inaccuracies, from the sequence of events to the characters. Colour Sergeant Bourne, for example was a young man, not the grizzled old veteran shown in the film. He was commissioned during the First World War, and died on VE Day, in 1945! Chard was described (I'm paraphrasing) as "the kind of officer one would leave behind if one was able to", and Bromhead was deaf; neither was he quite the epitome of British officerhood that he appears in the film, again being left to guard the depot because he was the Officer that his Colonel could spare the easiest. He'd described him as being hopeless. He was, however, an experienced officer, who'd been in S.Africa for a couple of years already. The men were all volunteers; no conscription in the UK until 1917. Regiments and battalions rotated around the Empire, and officers by 1879 were usually fully attached to their regiments, rather than rapidly purchasing their way through different regiments as had been the case previously, so they weren't second team players, as it were. There is a lot more on the authenticity of the film here. Although it is Wiki, it is very good http://en.wikipedia.org/wiki/Zulu_%281964_film%29#Historical_accuracy

I just read Michael Caine's autobiography and he addressed an interesting point.

He had actually served as a UK Army infantryman in the Korean War and was familiar with the British Army.

He was almost fired during the making of the movie because he would always keep his hands behind his back. The producer said it looked phony.

Caine says he served under some officers who always went around with their hands behind their backs because they were raised never having to do anything themselves; i.e., someone was always opening the doors for them, serving them food, etc..