Searching for Father and Mother of Ethel Cathleen Hillary Chapman of South Africa

@Ethel Cathleen Hillary Chapman. My grandmother Ethel Chapman is the direct descendent of one of the famous Chapman explorers in South Africa. After 5 years of research I'm still no closer to knowing the names of her mother and father. Ethel's mothers maiden name may have been Thomas. Grandfather Chapman was involved in the diamond mines in Kimberley and the Cullinan (Premier) Diamond mines. Her sister may have been Blanche Chapman. G Grandfather Chapman was said to have died in Nazareth House in Johannesburg.
Ethel was born in 1904. She married Cecil Anderson, divorced him and married an Edwards.
Ethel had Roma and Sylvia by Cecil Anderson. She had Maureen, Hazel and Errol with Edwards.
PLEASE, can someone ......... Anyone...... Help me with this.