Hi Marg Williams,
Leila and Gladys knew that they were sisters/twins.
Here is Leila May GARFOOT's obituary published 23 Sep 1929.
.... Wreaths were sent by... Mum and Una, Mother and Father and Family, Sister Gladys, Dad, Mum and Sisters, ....
http://trove.nla.gov.au/ndp/del/article/137790512?searchTerm... garfoot"&searchLimits=l-state=New+South+Wales
Mary