Information from Australian Electoral Rolls (Ancestry.com)
1930 NSW Cook - Botany
RENNIE Margaret Crawford, Excell St, home duties
RENNIE Robert, Excell St, stonemason
RENNIE Robert jnr, Excell St, Botany, motor-driver
1936 NSW Cook - Mascot ( have listed all on this)
RENNIE Dulcie Eileen,55 Frogmore St, Mascot, Home duties
RENNIE Frederick Stephen, 55 Frogmore St, Mascot, Packer
RENNIE Joseph, 55 Frogmore St, Mascot, Soap maker
RENNIE Joseph Michael Francis, 53 Frogmore St, Carter
RENNIE Margaret Crawford, 18 Smith Street, home duties
RENNIE Mary Eleanor, 53 Frogmore St, home duties
RENNIE Mary Ellen, 55 Frogmore St, home duties
RENNIE Robert, 18 Smith Street, Stonemason
RENNIE William Ernest, 55 Frogmore St, labourer
1936 Electoral Rolls details for Robert RENNIE jnr.
1936 NSW Cook - Botany
RENNIE Dorothy, 11 Tunbridge St, home duties
RENNIE Robert jnr, Tunbridge st, motor driver
RENNIE Alexander, 11 Tunbridge ST, machinist
I'll go back to the census records and paste all census' related to this family
cheers
Genie