@Blu3: That's very strange that they've just unilaterally given you a class 4.... I was under the impression that that decision was made after recieving evidence and confirmation of a condition, not just a questionnaire... Now that I think about it though, my initial contact with the nurse resulted in receiving a letter from AVMED to pass on to my doctor asking for a confirmation of diagnosis. My GP thought it was prudent to do specialist testing as he wasn't the one who diagnosed me, and so that's why I went on to do the challenge test before anything else. After I submitted the results to DFR I went on to do the pilot specific testing and assessment day. At assessment day the AVMED doctor said that he thought I had jumped the gun getting the challenge test done given that it may have been an unnecessary expense if I hadn't passed the pilot specific tests, though I would have had to do one eventually anyway when I made it to assessment day.
At assessment day they ask you even more questions and if you get any crosses you'll have to get more specialist testing done to satisfy the ADF that you're not a medical risk, but hopefully that won't apply to you.
From what I've heard you're not the only one to have complaints about the Perth DFR, though I have no first hand experience.