As far as I can tell, no. There are no recorded eyewitness accounts or other direct historical evidence of the incidents that I can find other than Gandhi's memoirs.
According to the article, "Transforming our townscapes: the Pietermaritzburg experience" by Robert F. Haswell, a historical marker was placed at the likely spot of the incident, but the location is based on inference. An older article published in the same journal discusses certain historical details of the incident that were inaccurately portrayed in the relevant scene from the 1982 biopic, Ghandi and includes a relevant observation, again based on inference:
the official who ejected Gandhi would probably have been Scots, not Dutch or Afrikaans
That seems to be about all we know, and unless a surprising new source of information emerges, all we will ever know.