I'm not certain it is clear. When I look at booking a one way Brisbane to Hamilton Island flight in economy for the date of my travel on the QF website I see a base fare and the following additions:

GST: Au$13.64
Passenger Service Charge (Dom) Au$8.79
Passenger Service Charge (Dom) Au$19.00
Safety and Security Charge Au$5,53

Excluding GST this comes to Au$ 33.32
This is approximately £18.80 which leaves the extra £9.30 imposed by BA for exactly the same flight unexplained to me.

I'm not sure where your quote in UK currency came from but the taxes and charges are clearly more expensive than that I'm seeing from the QF website.