That's a sad conundrum my Aussy friend.
Research this option. Don't order and/or ship a kit.
Order a barrel. Then later on order a lock.
Then later on maybe a trigger,, then a ,,,, etc,,,
Follow me? Is there a way to defeat the system like that?
Or, even if a local smith isn't "skilled" enough to build it for you,, to have one "involved" in the build would/could be installing a single screw. You could do most of the construction, then bring it to the smith to have that last screw turned in with a screwdriver, pay his fee for involvement and signing off on the document,,