Charlie: I think you have hit the jackpot. Denise Dobson is my mother-in-law and I am married to one of her two daughters, Carole (the other is Jane). Denise, or Denny, still lives in Johannesburg but Margaret Stevens(your Aunt) passed away several years ago.
I was in London a few weeks ago and visited the national Archives. Charles Stuart Kirton left Scotland through England on November 3, 1906. His occupation is listed as a baker. His age was 23 at the time of sailing.
In the 1901 Scottish Census he is listed as being born in McDuff, Banffshire. His occupation then is an apprentice baker and his age is 17 (probably born around 1884).
My wife confirms he enjoyed the "liquid gold". Do you have any more information on your side of the family? Are you still in South Africa?