In most airports, there is a separate check in desk for Qantas Club/Oneworld Ruby/Premium Economy for all Qantas flights. IIRC, Qantas does not have allocate a check in counter to a specific (with the exception of flights to the USA). In SYD, the counters (together with Business Class check in and First Class check in) are completely separate from the general economy check in area and are located on the other side of check in area D.
Thanks so much for that - was confused as I have only flown air Canada from Sydney recently so was going by the set up in that area - obviously as a home airport qantas has a different, more elaborate check in area. Cheers!