My father was born in Malmesbury, Western Cape in 1924 and his name was Hein (Hendrik) Slabbert. He had one sister, Gertruida. Both of them are deceased. My dad was a medical doctor and practiced psychiatry. I have three brothers, one whom is deceased. He was murdered in Pretoria in 2007.
The family crest is indeed as described elsewhere in this thread, and a copy of a manifesto drawn up by the VOC always hung on the wall in the "voorkamer" of my grandmother's home. This document contained all the names of the very first settlers in the Cape and dates back to about 1660. My grandpa was Koos "Uil" Slabbert, an auctioneer in Malmesbury. My cousin now owns it, she lives in Belville. (I live in the USA)
I was doing research on a book I am writing about Russia, and came across the word "slobodo" meaning "Fisherman" and I remembered that the name Slabbert, while being Flemish had something to do with fish or fishing. My father always said that the family originated in Prussia, so perhaps the root meaning of the word slob/slab comes from there.
By the way, I taught in Steytlerville way back in 1980 or 81, I was there for 6 months!!!