Thank you all for your advice and the links to relevant cases.
Mcgrath:
From a CASA point of you, you just have to follow the CAAP (or something just as good that would stand up in court) for ALAs, although I'm sure you'd know that sunfish.
My understanding is that CASA makes "recommendations" for ALA's. They are not written in stone and CASA does not "Approve" ALA's.
Just God help you if you run into something that shouldn't have been there according to CASA's recommendations, because then the area wasn't satisfactory according to AC 091 - 225.
http://www.casa.gov.au/newrules/part.../ac091-225.pdf