to rob and ken, yes I thought it might be a trick but I'm pretty computer savvy, I work in IT and I have seen a LOT of spoof emails. Let me tell you if this is a trick, it is a very good one, it comes from a apf.gov.au address and has a person named at the bottom so it's not some "phantom" sender, also the person named has both a daytime phone number and a mobile number so it will be very easy to check. Also, since when do they not do anything by email? My ebay account is registered to my email address, hence the easiest way to reach me surely? They aren't as behind the times as you thing.
Either way, I have replied to the email asking about exemption for astro use, I will post as soon as I have a reply.
I actually have been contacted by the APF concerning the import of restricted items in the past

so I'm taking any chances...
Cheers