I don't think many will know just how good he was because his career was blighted by the (imo correct) banning of South Africa from international cricket. He had a Test bowling average of 15 (fifteen) and all against Australia, I think and a first class bowling average of 19. That's better than Fred Trueman, I think. I certainly didn't know that. Even Malcolm Marshall's average in tests was about 20.
RIP.