That is strange that you have only 28 days to submit the results of your tests. I did a paper application and didn't pay attention to the fine print, and ended up submitting it a month early (apparently they will issue the visa a maximum of 4 months prior to your planned arrival in Australia) but I don't recall any 28 day deadline. I'm not sure how they can process your visa without it given that those results are one of the major criteria for obtaining the student visa (other than demonstrating you've been accepted by an Aus. university) I'd say it looks like they are willing to wait a couple days to receive the results of your medical. Something that could throw a wrench into this timing, at least for the panel doc I went to, they only courier results once a week. So when you go for your appointment, i'd find out if they have the same policy and do what I can to convince them to send your stuff ASAP.
AU's visa application process is very confusing. Here is what I have learned, may be it will clear things up for other students. Now keep in mind that I am applying from USA as a USA citizen. Things might be different from other countries, thought I cannot imagine them being very different than from here in USA.
First. You cannot APPLY for AU visa until 4 months prior to your expected date of departure.
Second. AFTER you have applied, AND have received an acknowledgment letter from AU visa svc.....you will have 28 days to complete your medical requirements of visa application.
2 methods of applying:
#1 Online ( I will highly recommend this method); and #2 via paper application.
Online method:
-File your application online.
-pay visa fees online.
-make appt with physician right away.
-take your passport, plus cash (very important), plus 4 passport size pictures to your physician along with filled out part A of required health forms.
-Make sure you remind your doctor to do ALL the blood work (HIV, Hep C, Hep B, VDRL). Some AU visas DO NOT require ALL blood work, which is why physicians forget about doing all these labs.
-It takes about 2 weeks for the physician to mail in all of your paper work.
-From then on.....I really don't know what happens....since I am still waiting for my visa!
Paper applications might be slightly different.
Also, things to know. If your country is under category 1:
-You DO NOT need to mail your passport to AU visa svc. You will be issued an electronic visa which will automatically scan with your passport at the airport. In rare cases, the visa svc may ask you to mail your passport, but again for most of category 1 applicants it will not be necessary.
-You also DO NOT need to send in a bank statement, unless the visa svc specifically ask for it.
Hope this helps.