Is the OP a ROP member at all? The redemption for lounge access is actually quite affordable (no status needed), being 5,000 for member entry or 7,500 for you and a guest. I'm not sure since the OP already has access due to their J ticket but its worth a try to burn some miles instead of paying $59AUD for entry, I'd give TG a call if its possible to use 5,000 points only for the guest.
https://www.thaiairways.com/frequent...-redemtion.htm