Hi,
We had to renew our daughters passport here, we arrived on a 457 and she had 2 days to go until the 6 month limit. It subsequently expired and we had to send off to NZ to get it replaced. The cost is actually the British Goverment ripping you off, nothing to do with Perth etc, as we have had to renew in Oman where we lived before and it was just as bad and took even longer because the application went to Germany. I must say though that the process here was relatively painless, I'd even filled in part of the form wrong (blonde, I know) and the lady at the post office waited patiently for me to correct it, checked it all, sent it off for us and we had it back in 2 weeks. Far better than wasting days of your holiday!