The Deck is a CX lounge, not the QF lounge. Also the OP notes the check in agents said they were only eligible to use the QF lounge, which I will generously call misleading.
ignore this bit, i have re-read the above
Originally Posted by
alex67500
The OP stated they're travelling in club, aren't the pier and the wing first lounges?
there is a pier J and wing J, as well as a pier F and wing F lounge.