I have typed this offline so some information is duplicated.
Mr Thomas
BROWN, 23 years, engineer,Mrs Margaret
BROWN 25 years, wife and Miss Mary
BROWN 2 years departed London on 1 May 1912 on the
COMMONWEALTH ticketed to Melbourne, via Cape Town. Country of last permanent residence, England. Country of intended permanent residence, Australia.
Australian Electoral Roll
Victoria 1914
BROWN Margaret Johnston 39 Sheffield Street, Coburg HD
BROWN Thomas Hunter 39 Sheffield Street, Coburg Fitter
1919
BROWN Margaret Johnston 92 Gheringhap Street, Geelong HD
BROWN Thomas Hunter 92 Gheringhap Street, Geelong Fitter
WA 1925
BROWN Margaret Johnston 73 Bassinghall Street, Victoria Park Home duties
BROWN Thomas Hunter 73 Bassinghall Street, Victoria Park Engineer
1931, 1936, 1943, 1949
BROWN Margaret Johnston 94 River Street, South Perth HD
BROWN Thomas Hunter 94 River Street, South Perth Engineer
1954, 1958
BROWN Margaret Johnston 94 Douglas Avenue, South Perth No occupation
BROWN Thomas Hunter 94 Douglas Avenue, South Perth Engineer
1963
BROWN Margaret Johnston 31 Elizabeth Street, South Perth Home duties
1968
BROWN Margaret Johnston 41 Beach Road, Marmion Home duties
Deaths
BROWN Thomas Hunter 71 years
Father George H Mother Elizabeth
District Perth 1959 Reg#3449
BROWN Margaret Johnston 82 years
Father Robert Mother Mary
District Perth 1968 Reg#4095
Birth
BROWN Jean C
District Perth 1923 Reg# 1923
Marriage Victoria
BROWN Jean Crawford
WRIGHT Kenneth Douglas
1942 Reg#5724
Marriage in WA
BROWN Horace J
McANDREW Dorothy P M
District Perth 1945 Reg#2006
I noticed a Mary Blaik
BROWN on the electoral rolls but not at the same address but in the same sub district, as Thomas and Margaret so this is now very speculative research. Her burial record at Karakatta indicates she was born c1909 so could be the Mary aged two on the passenger record.
Mary Blaik
HEAVEYhttp://www2.mcb.wa.gov.au/NameSearch/details.php?id=KO00178273Husband, Patrick Joseph
HEAVEYhttp://www2.mcb.wa.gov.au/NameSearch/details.php?id=KC00019584Marriage
BROWN Mary B
HEAVEY Patrick J
District Perth 1937 Reg#1206
The births to Thomas and Margaret in Victoria are not on the indexes to 1920.
Cheers
Cando