Hi Emma
No. The Panel Doctor doesn't contact your GP at all. Please see Forms 26 & 160, which are available via this link:
http://www.uk.embassy.gov.au/lhlh/health.html
The drill is that you are supposed to get copies of anything you need from your GP and take those with you when you visit the Panel Doctor. If you are on medication for anything, write the generic name of the drug on the list as well as the brand-name, because the brand-names are different in Oz. Put the dosage as well - as per what it says on the box.
If you have had to see specialists for any reason at all, get copies of their reports to your GP. The Panel Doctor will sift through them and sort out which ones need to be included in the Meds bundle, and will give the remainder back to you.
Cheers
Gill