NSW Number Plates

I had the same issue (car was originally from Canberra). Holes didn't line up with NSW plates (!!).
Just had to carefully drill new ones into plastic surround, making sure not to go through into the bumper skin.
 
You can also choose standard Black-on-White plates, which are a bit slimmer, at the same cost (ie. not custom with annual fee).

Could go either way I guess. In my case, the existing holes had been over tightened at some stage and threaded, so new holes in the plastic was a better option for firm fitment.