Just had my assessment day recently and was recommended for both my preferences (NAVY GAP, OP GBAD- ARMY). I am in the same position as haystack, just gotta wait til somebody pulls out, which apparently is likely to happen once TERs are released. For those interested, make sure you know what's involved. If you are joining because you think it sounds like a cool thing to do and had no real prior interest in service life you will most likely not get in. If you do, it's not a holiday, you will be trained alongside regular sailors/soldiers (it's a little different for RAAf - OE), be yelled at and generally work your arse off at all hours of the day/night. Once you finish your training it tapers off a bit, but you are still in the military and you will still be the "fuckin' gappie" for the rest of the year.
If you are still interested but get knocked back due to availability, you can still consider reserves/full time (that is, there is no time period before being able to apply again). Also keep in mind your aptitude test results and education history will, more so than regular applicants, influence your application as the whole idea is to suck us back in as officers once we have finished the 12 months.
Just a final word on the assessment day and what to expect:
Nurse
You will be required to sit an audiogram (hearing test), have your measurements (height, weight etc) taken. Be subjected to an eyesight test and a colourblindness test. You will also be required to submit a urine sample for analysis.
Doctor
The doctor will perform a thorough examination, and by thorough I mean thorough. Let's leave it at that.
Psychologist
This is pretty much to see whether you are suitable for the physical and mental demands that will be placed on you during your career in the ADF. Best advice is just answer as truthfully and comprehensively as possible.
Defence Interviewer
This is the final stage, you will be interviewed by a serving member, most likely warrant officer or equivalent. He or she will have the final say in whether you are suitable or not based on your performance in this particular interview and the day in general. There's not much you can do here, just know your stuff and make sure you are prepared for the ADF and understand what will be required of you. At the end of the day it's more a judge of your character than anything else.
Also, be prepared to wait up to 1-1.5 hours between each section. It is highly unlikely you will be there for less than 4 hours and could be there for over 6.