Damn. Someone at Ausway forgot to renew the custommaps.net domain, so the First Edition Melway is no longer online.
Apparently they haven’t realised yet, as it’s still linked from the Ausway site.
Some pages are in the Internet Archive (and also some from edition 5) though not all.
Update Friday: I was wrong; they’ve moved it to here (but they haven’t updated all their links yet)