Found some info (for anybody else in the same boat as i may be)

What if I can?t find my notices of assessment from 2004 to 2008?
If you cannot find your notice of assessment from 2004 to 2008, you may still be able to lodge your tax return using e-tax by providing us with some specific information when verifying your identity. To find out more about what specific information can be used to verify your identity, go back to the previous page and read the information contained under the heading 'Eligibility requirements'.
If you are unable to use the specific information to verify your identity, you can phone us on 13 28 61 between 8.00am and 6.00pm (local time) and ask for a copy.
When you phone us, you will be asked to prove your identity by providing your tax file number (TFN) or your full name as well as some other personal details.
When we have confirmed your identity, you may request the following information from your most recent notice of assessment (issued before 30 May 2009):
your TFN (if you cannot locate it)
your full name (exactly as it appears on your notice of assessment)
the date of issue, and
the sequence number.
Alternatively, you can:
ask us to post you a copy of the notice of assessment ? phone 13 28 61
visit one of our shopfronts and obtain a copy in person.