I contacted a book binder in Adelaide on this very problem.
He advised that he could bind and provide the binder for the "pages must be permanently bound and not removeable" CASA requirement. A leather binder was available also.
After the initial binding you would need to send it back every year with a years worth of pages for binding - not what I consider an ideal situation.
I have not progressed any further than the phone call. But as my handwriting is resembling scrawl these days; this could be a possibility. (I didn't ask a price at the time)
will post if any further progress