Living in the UK, its always been a pain to get certain bra sizes. I want with the fit I want,(working in Thailand I simply did not shop for Lingerie), now living in Australia and things aren't fairing that much better, even the company I’m designing for, doesn’t recognise my size!
A quick search on the net to find websites that have a variety of styles and sizes: www.bravalingerie.com.au - they start from a D cup so specialise in the Larger cup, and go down to a 28 inch (size 6) back. They do swimwear and clothing as well.
www.zodee.com.au – this sells more branded stuff, and is not solely aimed at the larger cups but they still carry a broad range of sizes.
www.brasnthings.com - this sells a whole load of lingerie and bedroom attire, if you’re looking for something of a bit of a younger design then it may be worth a look and if you’re a 30DD (I should now say 8DD), they have a good sale on.