Wagemakers Vallei , Cape of Good Hope

I would have thought as it would have been named at the time of the event involve

Wagenmakersvallei was a general area, like Land van Waveren, Drakenstein, Riemland, Karoo, Swartland, Namakwaland, etc. In this way for example, Nieuwveld was the first name of the region in which Graaff-Reinet was proclaimed after the settlers came, though the original name actually included the wider district, including where this town later existed. Like the others, "Wagenmakersvallei" was not used at the time to refer to a city/town or single settlement. I usually enter these on the address as a County.

You're perfectly correct, Phillipp!