I was at Melbourne - and they tested on Day 3 and transferred late on day 3.
Different clinics do it differently - but they are probably right to have just one procedure at each clinic, since it is really, really fiddly, and so much depends on the skills of the embryologist - so you want them to be very, very practised at whatever method is used.
The day 3 biopsies require drilling a hole into the embryo with a laser and sucking out one or two cells. They have 2 big disadvantages - it is more difficult to get a test that works on that tiny amount of genetic material (onja's 2 years to formulate a test, and my 3 years to formulate a test are pretty typical), and secondly not all embryo's survive the test.
The advantage is that some embryos that may not make it to day 5 in a culture dish could make it inside a body.
If I remember correctly you could manage to have healthy bubs just by sex selection though some of them would be carriers - if that is the case then you wouldn't have the test development marathon if you were to swap to a day 3 clinic. As far as I know there is a big waiting list for PGD at both Melbourne and Monash -but it wouldn't hurt to call them and ask. Melbourne has a specific PGD coordinator, who would be worth talking to.