(yes wiki moron that would explain why the centre for social policy research is at unsw.)
of course you can transfer if your marks are good enough. but the competition is pretty tough, coz that's wat lots of ppl plan to do. just because the cut-off is 90 doesn't mean there aren't heaps of ppl with high UAIs. and plus, you have to compete with people who could have got into law in the first place but decided not to, have started the degree and decided they wished they had and now apply for it taking the lovely spot you hoped you'd get.
unsw is very flexible, and the degree covenors are very approachable and will help you organise your degree so you go where you need to go. You do realise though that everyone has to do law subjects as part of international studies even if they're not doing a combined degree anyway right? There's a core component to do with international law and human rights....