The following quote now also appears next to the International Business Lounge Access for WPs on the
QF website:
Must be travelling, not necessarily on Qantas, British Airways or Jetstar to access the lounge. From 1 April 2008, you must be travelling on the day with Qantas, Jetstar, British Airways or any of the other oneworld members airlines to access the lounge.
I hope this is an error because the E-Mail was saying there is still anytime access to international J lounges.