Your travel agent (or BA / QF if you bought the fare from them) will be able to confirm. If you have a printed e-ticket receipt from your travel agent or a BA / QF office you will find the baggage allowance printed to the right of each sector. If not then call the agent and they should tell you. I would be cautious of an e-ticket receipt printed from MMB.

Collection of xbag revenue is not at all scientific and the principles of give and take apply. BA may well apply the most generous allowance regardless. Or they may not.