Yeah but lest we forget USyd and UMelb are the second best universities after ANU (in terms of international ranks) and they're around 50 something whilst ANU is 16. Obviously ANU > better. I'm not sure about law, but in terms of prestige, ANU is much better than USyd (which is lower than UMelb by one).
Sydney, UNSW and ANU all accepted me into graduate law programs, Sydney as LLB, UNSW and ANU as JDs.
Guess what, I chose Sydney coz of prestige as well as convenience (more emphasis on the latter actually). NOT ANU. Yet again prestige of the law school does not mean it's a good law school. It's the name, history, connections, etc.
Here's are 2 simple tests I made up on the spot to test for prestige:
1. THE CONTROL: Ask any law student at X Law School, where X be any University name, which law school is the best (or would you prefer to be in), the law student at X Law School would most probably (I emphasize most probably, coz of biased preferences, loyalty to the uni, ignorance to other unis etc.) reply that X Law School is overall the preferred choice.
THE EXPERIMENT: Now, ask a group of ANY random yet reasonably knowledgeable people, such as a typical mother with kids who went to uni/ high school, or any non-law student or friend, law clerk, family solicitor who did your dad's property conveyancing etc, WHICH Law School would they pick if they were to advise a friend/ oneself, to attend law school.
WHATEVER THEY PICK, should be the one with the most prestige.
2. Go wikipedia famous lawyers, judges, politicians (or any famous law related people) which law school did they graduated from (ONLY FOR obtaining the LLB, NOT the BA or BJuris, Engineering degrees or LLM coz you're not looking at other faculties or post-law degrees). Which ever law school gets mentioned the most wins.
Neither test 1 or test 2 by itself is conclusive, nor is the identical solution of both test 1 and test 2 conclusive either. BUT if Both test 1 and 2 points to the same law school, you're PRETTY MUCH SURE that that law school has the most prestige. And I'd also assure you that ANU won't be the answer, at least not for test 2.