I've been asked where exactly the ruins from my previous post are (thank you for taking the time to comment by the way). Here are some roughshod directions, which I hope will make sense.
If you're travelling the N4 from the Machado Toll Plaza eastwards towards Waterval Boven, take the Lydenburg/Nelspruit (Schoemanskloof Road) to the left. When you're almost at the summit of the hill, on your left, along the side of the forest you'll notice in the distance some small ruins. Just after that is a sand road to the left, take it, and travel with it until you're above the ruins... there's a gate in the fence and you'll find that you have an incredible view of the entire valley, all the way to Imemeza (SeSwati for "place of shouting"), the mountain behind Waterval Boven. Either before the sand road or not long after it is a signpost for the forest on the left, which I believe is 'Camelot'. Next time I'll take a GPS reading to highlight the entrance to the sand road. Let me know what you think.
As yet no one really knows just how old these ruins are. If you clink some of the rocks together you'll hear that they are like iron stone and are very heavy. Respect the space and leave everything exactly as it is - take only photographs, leave only footprints. And enjoy...!