Are you sure about the straight 30rd magazines only being produced in Canada? I'd be surprised at that as the new ones all seemed to be in the standard Aust Ordnance type NSN's and wrapping. And Oz were already producing zillions of the standard mags...... The reason Australia
didn't produce the curved magazine was, as I understand it and told to me while in Oz, was that the RSAF held the IPR on all things Bren INCLUDING those for the UK
designed curved 30 round magazine. That's why Oz produced something similar..... but! Simply in order to by-pass the formalities. There was a fair bit of this underhand (but clever.....) dealing when it came to the L4 Bren of course. A good example of how NOT to treat your allies I say! Maybe RSAF should have acted more like Sterling and the F1 magazine saga. I rarely saw an L2 in Malaya with Aust, NZ, Gurkha or Malayan Infantry (although there were a couple with the Aust and NZArtillery somewhere). It all seemed to be Mk3 Brens and L4's. Maybe that was a strategic move - above my pay grade.