I also noticed a wife buried with husband that belonged to you as well. At the top of the page it will give you the province and town were buried, you could try and contact local museums for any further info.
Keep in mind: 1. Many graves in South Africa have been damaged / decimated, so not always head stones.
2. Local town municipalities should have maps of plots BUT in many cases no interest is shown and queries not replied to, so do not expect much!! On the other hand, you might be pleasantly surprised.
3. Noticed the families had settled in Orange Free State and Transvaal areas, both were independent Boer republics at that stage.
Regards