Hello and welcome quokka,
We are pretty limited dealer-wise here in Adelaide aren't we?
There's Adelaide Optical in the city or Shell-lap supplies at the top of Henley Bch Rd. I've always bought from Bintel, AOE or Andrews as they have the cheapest deals + postage compared to the local dealers.
A 12" basic GSO generic dob was around $1500 at one shop as opposed to $799 + freight around the mail order outlets!!
I mentioned this to the local dealer, but all I got was a "ce'st la vie dude!!!" - they can't compete with the high volume turnover of the big guys.
I've found all the interstate dealers to be quick and easy to deal with.
Add between $50-100 depending on size/dealer for shipment of a large Dob.
Cheers and Good luck.
Doug