I'm flying tomorrow from London to Tallinn via Helsinki on an economy superlight fare. I'm oneworld sapphire with Qantas and my partner ruby with British Airways and I entered these frequent flyer numbers when booking. As I understand it this oneworld status should entitle us to a free carry-on bag, but manage my booking is only showing a small bag and no carry-on bag, but with the option of adding a carry-on bag for £11.60 each per flight.

If I've understood previous posts correctly it may correctly show the carry-on bag allowance for non-Finnair oneworld status. I was intending to check in online. Is there anything special I need to do to in advance to ensure we can bring carry-on bags onboard, or is it just a case of showing our frequent flyer cards at the boarding gate?