Repair of small arms would have been done by unit Armourers, and I think at the time of the Boer war major repairs and replacement would have been down to the Ordnance Corps (later by Royal Electrical and Mechanical Engineers).

The Balloon Section Royal Engineers operated a static observation balloon up to the Relief of the Siege of Ladysmith.

When that happened the war became more mobile, so 3 Field Troop was formed to operate from waggons to build and repair bridges, fix railway lines, build blockhouses and the like.

They would have needed Carbines for camp guards, self defence, putting down cast horses and no doubt for discreet foraging.