Now isn't that remarkable. I looked at the S.A. Agriculture Information Service brochure titled "Spinach." First of all, the photograph looks all the world like Swiss Chard. It is certainly not in any way
Spinacia oleracea. The text makes no acknowlegement that there might be anything else called spinach, but it does state that spinach (the Swiss chard looking thing they're talking about) is often confused with Swiss Chard. Okay. They're in the same family, and "perpetual spinach" is one name for chard. Other references note that Swiss chard,
Beta vulgaris, is incorrectly called spinach in S.A. I'd show a photo of the S.A. "spinach," but I can save the space. Just look at a photo of Swiss chard. Sorry Pretoria government ag guys. It's Swiss chard.
In another place, I do see instructions for growing "English spinach" in South Africa, and it appears to be
Spinacia oleracea, the spinach we know outside S.A. So it appears that chard or a close cultivar became the "spinach" of S.A. Spinach doesn't do well in hot weather, goes to seed quickly, but Swiss chard is perfectly happy in the heat and is favored here in Texas.
You might indeed be getting genuine spinacia "baby spinach," since it would fall into the microgreen category grown in greenhouse.
Actually, I prefer "Malabar spinach," the vine
Basella alba, no relation to spinach, to spinach. It likes heat and humidity, and the leaves don't cook down to mush like spinach can. Grows easily and often reseeds itself.