OK, all went well with the social visa application from the embassy in Sydney.
Used version of a sponsorship letter I found on this forum (same form for whole family).
Usual passport photos (which I made myself - very easy and very cheap!)
Ticket denpasar/darwin dated within 180 days.
Just a note: they are absolutely militant about it taking 5 days to process. there was a woman ahead of us who was absolutely distraught but they wouldn't budge.
cheers, Phil
I just got my Sos Bud done yesterday in Singapore (well, my agent did, while i was shopping :P), without any return ticket... No problem at all...