FYI,
They are not employed by SAPOL, technically or otherwise. They are empowered by the Road Traffic Act to act in certain matters on behalf of the Transport Minister, just as the SAPOL are, but it doesnt make them employees of SAPOL - maybe this is the problem with them?.
This is an act of Parliament, not criminal or common law. Regency inspectors are public servants, now called public sector employees, probably because they dont know what service is.
It seems pretty obvious to me, when an ex-employee doesnt even know what powers they have, or where their charter is derived - that there is something very wrong.