If I remember correctly, Naturelink operate a Skyvan. Not too many operators of them left out here. There were two being operated from Durban in the early 90s, but one went to Aus for geophysical conversion, and the other to Europe for paradropping.
It may never win a prize in a beauty contest, but it was an honest airplane, if you could close the door, it would fly, even out of Gauteng.
We once took 2 PT6, 2 props, 3 drums of fuel and associated engineering equipment (jacks, engineers etc) from Lanseria to Paradise Islands to retrieve a Kingair that someone had managed to immobilise but breaking off the nose wheel (at 96% N1) in the sand. It took us straight to FL100 without a compliant.
Masterful aircraft.
Good luck.