So, I've started on the SA acrchives - here's one possible hit
DESCRIPTION YOUNG, MARGUERITE ELIZABETH FLORENCE. BORN WEEDON.
REMARKS SURVIVING SPOUSE DOUGLAS ARTHUR YOUNG.
And this one
DESCRIPTION YOUNG, DOUGLAS ARTHUR.
REMARKS PREDECEASED SPOUSE MARGUERITE ELIZABETH FLORENCE YOUNG. SURVIVING
SPOUSE ANNIE YOUNG (BORN MARAIS FORMERLY VENTER).
If that is them (and I can't see any other possibilities), then Margaret (or Margarita) died in 1964, and Arthur remarried, and died in 1974. There're two ways to get those files - place an order through the EGGSA, or head to the Family History centre in Parktown. The estate files will have childrens names, and often parents names.