We all knew nothing when we started, but I can't suggest where to look for a marriage if I have no idea when people lived. If the poster knows where Catherine and Michael lived in Australia, he or she presumably knows about when they died, and therefore about when they were born--1820s, 1830s, etc. Knowing that allows someone to suggest whether the civil or Griffith's index would be helpful, and whether church records are likely to survive. I'm not trying to cure anyone, just trying to get more information. If you can offer useful suggestions without knowing when the couple lived, please do so. Diane