Also you cannot book those CHEAP fares on BA if you are overseas!
They require an UK Billing Address.

I check the same dates on the Aust. BA Site. and it gave me the full publish fare with NO CHEAP Options.

Also when used with the DONE4 fare I can agrue at the checkin counter to give me the same Baggage Allowance (2 pieace TOTAL 64KG vs 20KG!!!!)

I am sure I don't want to pay for the 44 extraKGs