Chris ... you go to an approved car shop with your reg docs and they'll make you one while you wait ... or you can get them made up off the web with the same proof.
K
Ps ... with the old B&W ones there's nothing to stop you painting your own in your shed as long as you stick to the proper sizes and spacing
While you wait

I expect they are not a pressed metal design like here. My front plate got badly damaged in an accident, the panel beater bent it straight but it looked shocking and I half expected to get pulled over for not having a clear to read plate. I had a number plate matching the car for my bike rack that cost $50, I could either get new plates straight away or wait 6 weeks to get ones made to match my old ones for the same price. As I had the bike rack plate I decided to wait 6 weeks rather than have to replace it.