From the BOM site, in the aviation weather section:
Accessing Meteorological Information for Flight Planning
Airservices Australia is the official provider of the Aeronautical Information Service which includes the delivery of the Bureau's aviation meteorological products. Therefore, all information for the purpose of flight planning should be obtained from Airservices Australia.
Quite clearly states ASA deliver the BOM info and we "should" (not must) obtain wx info from ASA.
I'd happily argue that aviation forecasts obtained via the BOM would be perfectly acceptable- especially when the official provider cannot well, provide!