Hardy EASTHER (b. 1897)'s parents were Frederick EASTHER and Elizabeth HUTSON.
Lettie Rose b. 1890 was his older sister. She married Ernest Rupert Roy BAWDEN in 1912 and Gwendoline was their daughter.
http://nla.gov.au/nla.news-article35177282 (engagement notice)
Not sure if she and Ian divorced but when he died his wife's name was Joan.
1972 / 179A/7068
HENDER Ian Thomas Lance
Joan Elizabeth Janet HENDER [W]
Adelaide
Her death at Ryerson Index site - notice may contain clues:
HENDER Joan Elizabeth Janet
Death notice
07DEC2009 Death, late of Torrens Park
Adelaide Advertiser 09DEC2009
In case you haven't seen it, Frederick EASTHER's death notice:
http://nla.gov.au/nla.news-article92357302 and Elizabeth's:
http://nla.gov.au/nla.news-article43488161PS I am not related