Found this bottle on the folly on 2 September 2020.
It is 18.5 cm tall and has embossed lettering "THIS BOTTLE IS THE PROPERTY OF GOLDBERG & ZEFFERTT LTD". It has G & Z, the number 4 and a maker's mark embossed on the base.
I did some research ........
GOLDBERG & ZEFFERTT LTD.
the original company was known as Horwitz & Co Niagra Steam Water Works and they had the logo om a leaping lion. In 1899 there was a name change to Goldberg & Zeffertt Ltd.
http://www.antiqueaddiction.co.za/product/hybrid-codd-hamilton/
According to the article above on the Antique Addiction website, during the early 1930's Golberg and Zeffertt was the first consessioner bottler of Coca-Cola in the Country until 1934 when Coke decided to manage their own affairs. They can't confirm if the G & Z bottles were the first known bottles with paper labels that were used to bottle Coke ...... but they might just be!
cola.co.za/know-us-better/coca-cola-globally/history
I think I've found one of the very first bottles in which Coca Cola was bottled in South Africa in the 1930's, right here in the heart of Johannesburg
When I did further research I also found that there were 2 learners in the school magazine in 1942 with the surnames Goldberg and Zeffertt.