Just get an Italian to do the catering and you'll be fine.
That's pretty simplistic, there are plenty of atrocious italian restaurateurs and caterers, like most sectors of food.
MTR some of the best wedding food I've eaten has been when high quality but casual food has been served, I find the sharing aspect helps loosen everyone up.
All depends on the wedding and how formal it is, there are plenty of good caterers in perth.