I'd been having trouble importing larger post code areas, some about half the size of the NT, if I manually downloaded along the border it would take ages needing hundreds of downloads.

However I found a simple way to do it, using JOSM I converted the postcode osm file to a GPX file and then right clicked on the GPS layer and selected download along track.

This takes the hard work out of downloading up to 212 areas just to add the boundary.

Hope this helps someone else, or encourages others to help import postcodes :)