Thanks I have been investigating the section between your co-ordinates and 28 21 32.49 s and 30 34 34.53 E (about 400m down river). Some refer to this point as "Masondo". I have visited this area before but felt that the gap was a bit wide (about 2.5-3.0 metres est) and the "runup", launch and landing points are tricky. In addition, the rock is very hard and does not look like it would have eroded much if at all over the last 132 years. (Just my opinion). The river was in flood so the rocks would also have been very slippery, so not something I would try (but I'm not brave and also not a Zulu!). However, a tree or branch could easily be thrown across the gap.
I will investigate further next weekend. and let you know
Some references suggest a crossing point not far above Fugitives Drift (the river also narrows into a gorge) but I would think it unlikely that they would have taken such a long way around, and the approach to this point from the Zululand side is not a "natural" route to follow on foot.