Hello Lorna
I am assuming you are asking about content and buying certificates from NSW. Certificates for the mainland eastern states of Australia (incl NSW) are very useful and contain similar information to 1855 Scottish Certificates - from shortly after the start of civil registration. In the early years of civil registration some was missing but by the dates you are quoting - it would all be complete. Your marriage certificate should include
For Bride and Groom
Name, Occupation, usual residence, status, place of birth, age, father, mother, father's occupation
General
Date of marriage, place of marriage, religion, witnesses, minister, other details
Certificates are somewhat more expensive than on SP - you have 2 options
Buy an official transcript - you can do this online with a credit card - $25AU which would be about 10 pounds
NSW also have transcription agents. They send email transcriptions - usually sufficient for family research - but not a legal document. Cost $15AU There are 3 agents - but I think only one has online credit card facilities
http://www.bdm.nsw.gov.au/familyHistory ... ptionAgent You can check them all here - I use Laurie Turtle, but he doesn't have online credit card unfortunately. I simply phoned him with my card & I then order by email whenever I need a transcript
Death certificates can be even more useful IF the informant knows the details for the person who died. The online death index in NSW will contain the parent given names - have you checked these for your folks?
The only John Curzon listed 1904-1976 is
20698/1925 CURZON JOHN - parents Joseph and Emma, location Manly (Northern Beachside surburb of Sydney) - Your John could have died after 1976
There is a death for a Charles
4363/1965 CURZON CHARLES JAMES E parents James Eugene and Harriet Susan, location Sydney but there is also a Charles born 1906, parents listed as James E and Harriet - so the names become a little confusing. There is a James E born in Sydney 1882 parents Charles J and Mary J - I wonder if he is the man who married as Charles J E in 1904.
Trish