From Electoral Rolls:
1949 at 4 Bennett St, Dee Why
Joseph CROMBIE, labourer(this is the only Joseph CROMBIE who does not use a second name, so I am assuming it's him. In same general area of northern Sydney suburbs as Narrabeen - see below)
1954 at Pacific Lodge, Fisher rd, Dee Why
Joseph CROMBIE, wardsman
1958 at 89 Warraba Rd, North Narrabeen,
Joseph CROMBIE, no occupation given
Nellie Geno CROMBIE, home duties
I think he may have been married before Nellie.

There is a death notice in 1945 for Agnes CROMBIE, wife of Joseph, resident at 4 Bennett St, Deewhy which is the address for Joseph in 1949
http://trove.nla.gov.au/newspaper/article/17959585Marriage:
NSW 1929, #17553 reg at Newtown (suburb of Sydney)
joseph CROMBIE, Agnes DOUGALL/DONGALL
Obviously you would need certificates, but, as I have already said there are lots of men of that name but all seem to have a second forename.
Judith