The roll for the Natal Volunteer Transport Service is at the beginning of WO100/261. It consists of 4 pages. 87 medals awarded, 64 issued. All to Drivers except the very last to a Conductor. 122 clasps awarded including RoL and DoL.
The roll for the Natal (Hired) Transport is in WO100/216 between pages 154 and 158. All to civilian transport conductors. 87 men listed. 62 medals awarded, all without clasp.
The NVTS came into being at the start of the war by commandeering the men and animals of the Natal Public Works Department (more here ).
Would the hired transport have comprised additional men needed to transport Buller's force? That both gained entitlement to the RoL clasp suggests they were contemporaneous. The fact that they were separated out into a different unit suggests they did not want them to be part of the NPWD when they were no longer needed?