I have not seen Zulu --- it's on a very long list of things I want to see
in fact, now that I think it, the only movies I've seen a young Michael Caine in are Dressed to Kill and Sleuth
If you do go to watch it, just be aware there are two films. Zulu Dawn (starring Peter O'Toole, which is about the rather disastrous (for the British), battle of Isandlwana, and then Zulu is about the Battle of Rorke's Drift. A lot of people get the two movies mixed up. Of the two I would say that Zulu is the more enjoyable film, although both films have their merits.
I knew some of the people who worked on
Zulu Dawn (1979) and one of them told me that the production was bankrupt even before they started filming and people weren't paid for weeks
There was a silent SA production called
Symbol of Sacrifice which is also about the battle of Isandlwana, made in 1918: one of the few surviving silent films in Africa.