There are now two tiers of ‘recommended’ vaccine for under 60:
General recommendation (eg you don’t have a GP) - Pfizer
Specific GP recommendation (provided you had ‘lengthy’ chat with your GP) - Astra Zeneca
I do note NSW CHO indicating Astra Zeneca will be available for over 60, and second doses at mass vaccination clinics because they don’t have the capability for the ‘lengthy’ GP chat. From this I surmise if any new GP takes a full medical history then they are in a position to give a specific recommendation.