What kind of money are you looking to spend? Do you want to go all out and do the ultimate 'buy once buy right' and get some IWF gear? Or do you want the cheapest that will do the job and still probably last a good while?
As you're considering premium plates, you probably don't want those super cheap fat no-name chinese bumpers with little bronze inserts. I don't blame you.
I personally own Pendlay black elite plates, because I was willing to spend the extra over econ style plates, but not willing to spend an extra few hundred to have coloured rubber haha. I currently have the appropriately coloured electrical tape around the edges of them which actually looks fine and works well.
If you do want to go the IWF route, which would probably be in a similar price range as Ivanko except Ivanko aren't certified. I know that JME used to sell Zhang Kong which is great gear (used in 2008 Olympics, trained on by Chinese monsters), however I notice their site has changed and they only have Force USA nonsense on there, whatever that is. Maybe enquire if you're interested.
Underground Elite used to/still has Werk San gear, another IWF company. I notice they too are only stocking Force USA now, what the hell! Enquire there too if you're interested in Werk San.
There are a few sites to get DHS gear from, which is the other Chinese IWF brand, also used at the 2008 games and trained on by the Chinese. I'm seeing it used in major competitions a lot more nowadays, USA Nationals used it recently. I was going to buy DHS before I bought Pendlay but I think the price went up so some sites stopped selling it.
There is apparently an Eleiko dealer in Australia but their site is dodgy as hell, I wouldn't trust it.
The last IWF company is Uesaka, used in a crapload of olympics and worlds etc. You can get it from here
Uesaka Barbells: Training Bumper Plates I just looked at the american site, and somehow, the australian prices are cheaper. That never happens. For anything.
If you want to spend less money, and I don't blame you, then Pendlay is a great option. They have benefit of me knowing they've been slammed every day for years in American gyms like California Strength, and now MDUSA. Plus Glenn Pendlay is a great guy.
To me, the Pendlay gear seems to be about the best value for money. Also the shipping on muscledriveraus is actually really low somehow. Many times I have ended up not buying things from Iron Edge because the shipping is so expensive. Maybe if you live near Iron Edge then shipping wouldn't be an issue.