What would be the most plausible POD, following the death of Shaka kaSenzangakhona, for the Zulu Empire to develop the necessary means to repel the British and remain a native African nation that lasts to present day?
I'm afraid that such a PoD would have to be very early in order for the Zulu to have a chance of resisting the british and actually surviving. While they may initially repel them, actively retaining total independence is very difficult for the Zulu.