The photo that was misidentified as British soldiers at Pretoria is marked “Artillerists, 1900 War”, and is signed by the photographer Jan van Hoepen of Pretoria. Other photos by him, such as the picture of the Bren Brandwacht commando on Spion Kop, and the Netherlands Ambulance team at Modderspruit, were signed the same way, so this picture could have been taken anywhere. Van Hoepen, by the way, took the famous photo of Louis Botha under a tree, that is on Botha’s wiki page.
See Van Hoepen Photos: https://commons.wikimedia.org/wiki/Category:Photographs_by_Jan_van_Hoepen
About this group: This looks like a crew to service a Long Tom, which required at least 9 men at one time. 5 are wearing uniforms, 4 of which are regular Boer Police uniforms, and one, (the reclining man to the group’s left,) is wearing a tunic with an 18 button front from the full dress artillery uniform of the Orange Free State Artillery. The rest are in civilian clothes.
(Correct my guess if I am wrong.) The spotter is on the left with a spyglass beside his flap holster. The man in the center with the white turtleneck shirt, has over his shoulder a thin leather strap for a small pouch that holds his sighting tools. The tall man offering him the pipe tobacco? Well, he’s the commander of this unit, no?
Thanks for the response. I read the term you call “artillerists” as “Artiller-ISTEN which would be Germanic.