I have been unable to find any verification that this song was sung during the 'Boer War'. All 'evidence' seems to be anecdotal.
Its early association with the Scouts leads me to think that it originated with Lord Baden-Powell and the early Scout movement, after the War.
Any Afrikaans version would be even later, if my presumption is correct.

In British Columbia, a form of the song has survived, "Swimming to Victoria."

The tune could be Afrikaans- perhaps it may be found at the very extensive Afrikaans folk song site, "Ons Blêrkas van Afrikaanse volksmusiek."
http://esl.ee.sun.ac.za/~lochner/blerkas
Ons Blerkas