Mattyl. It was my board in about 1990 that introduced the automatic airworthiness acceptance from five leading aviation countries. This was opposed by a number of senior CAA bureaucrats.
Up until then properly FAA certified aircraft such as the Beech 1900 could not fly here.Ask Max Hazelton. Read the relevant chapter in Two Years in the Aviation Hall of Doom.
In those days people such as Mel Dunn resisted the affordable safety fact. CASA appears to be doing that again.