Renault worked successfully as an author from the couple’s arrival in South Africa in 1948 through 1983. Her earlier British reputation as a writer of sensationalist bestsellers faded, and in 1983 she was listed as one of the famous alumnae who had brought the Radcliffe Infirmary Nurses' Home much honour. Starting in August 1983, Renault became seriously and then terminally ill with lung cancer. She worked to the last to try to complete a final novel (which remained unfinished; the manuscript did not survive) but had to go into residential hospice care. She died in Cape Town on 13 December 1983.