About Dorothy Winifred Buck
"of the Buck family, there was also a daughter Dorothy, who died when she was about 17 from Rheumatic Fever and is buried in Bloemfontein"
Source: Anne Fairbanks
Susan Margaret Buck nee Greyling and her three children (Beatrice, Dorothy and John) appear to have left England on 2 Oct. 1915. The passenger list for the "Saxon", a Union-Castle Mail Steamship that traveled from London to Cape Town includes a Mrs Buck, aged 25, Miss B. Buck, aged 5, Miss D. Buck, aged 4, and Master J. Buck, aged 2. These initials and ages match up with those of Susan and her children.
Source: UK, Outward Passenger Lists, 1890-1960, Ancestry.co.uk