Just putting the birth registrations for reference
MOSS, DORD ROSE NUNN
GRO Reference: 1905 D Quarter in IPSWICH Volume 04A Page 1021
Dora married on 17 December 1921 at the Methodist Church Mount Barker in Mount Barker, South Australia, to Rolan (Roland?) Horace Argent. Her father is Albert George Moss.
MOSS, BEATRICE MAY NUNN
GRO Reference: 1908 S Quarter in IPSWICH Volume 04A Page 1063
There is a marriage for a Beatrice May Moss on 26 September 1936 at St Cuthberts Church Prospect, Adelaide to a John Albert Lush.
Beatrice's father is given as George Albert Moss.
Parents marriage with father's names the other way round:
Marriages Sep 1904
Moss Albert George Ipswich 4a 1865
Nunn Laura Maud Ipswich 4a 1865
I can't see any travel records for when the girls first left.