In NSW if you amend a certificate there is another charge if you want a new certificate. After all, it is not the department who has made the mistake. It was the informant. Also I have found here that old BDM's often have 2 if not 3 registration numbers. I have been told that one is for the Parish registration, another for the county, and the third for another area division as well.By using the first(parish) number in very old certificates, it is possible to actually locate which church the registration took place in.So it seemed the proper way to register an event was to do so in all these areas. Don't know if Victoria is the same. Margaret