BK-WOL?
G'day Hoss & Aussie Andy
Harbour Bridge is HBB and as far as I can tell, HBG is 'Hamley Bridge', which is a helicopter landing site.
For an airways clearance ask for one when giving a taxi call on BK ground. They should have it ready for you when you get to the runup bay. There is a NOTAM I'm sure you've seen (C201/02 REVIEW C146/02) which eliminates the requirement for GAAP taxi calls unless certain requirements apply, eg an airways clearance.
Cheers
LT DT