3K is in T4. You'd have to check in/drop bags in T4, get over to T1, use the lounge then get the bus back to T4 for the flight. and that's assuming it's a flight in the late afternoon/evening when the QF lounges are open.
QF2 arrived early (it was meant to land now). Got to the QF F lounge. Had no issues getting in for QF4025/JL36 with a BA issued boarding pass. A quick glance has the lounge at about 30% capacity at the moment.
At the rate people are entering the lounge, it's going to be full in the next hour.
