The UK accept any JAA Flight Examiner (not instructor!) to sign the revalidation (by experience), or conduct a renewal check flight and sign for it.
If revalidating by experience, you have to have a 1 hour dual flight with a JAA Flight instructor, before getting the JAA/FE to sign the revalidation.
Try to find an OZ club which is approved for JAA training - they must have/know a JAA/FE.
If not, then maybe go to NZ to find a JAA/FE. I'm sure I've seen advertisments for JAA approved training in NZ.
Remember the form 1119 - you can find it on UK SRG's web site. Both you and the JAA/FE must sign it, and it must be sent to UK SRG.
The JAA/FE must keep records of this for 3 years.
I would suggest you keep photocopies, too.
Good luck.
GB