Are you certain this is sweetgum (Liquidambar)? The two common species in commerce (American and Oriental sweetgum) have leaves that are vastly different than these -- which look EXACTLY like Acer rubrum (Though how any of the sweetgum or the American red maple would get to S. Africa, I don't know).
Def a Sweetgum seedling, I have a bunch same size little bigger maybe, and up to 6' BnB.I have a sweet gum in my backyard and it gets suckers on the roots all year long. This is consistent with the first few leaves of a sweet gum. As the next few sets of leaves emerge and get larger you will find that they will look more like the typical sweet gum 5 lobed leaves.
Well things could be different around the world, but here are Sweet gum seedling leaves.And these are on one that is 12 years old.Serrated. So until your Red Maple gets Gumballs on it, it will be a question.What I have found on the net is that a sweetgum has no serrated edges where the red maple has