I was there last week around lunchtime (the day before your post) and did not even bother looking if the Qantas lounge was open.
Used the CX lounge in Concourse D and from memory there were only 3 people including me in the lounge. Would have been much better off in the Qantas lounge.
Getting a little OT I know, but will be using BKK flying CX to SIN in mid April, travelling with the wife and a 6 month old. Anyone know if Cathay are kid friendly when it comes to guest count? If not lucky then the QF lounge will be open for the departure.
PS LTG flying Y.