Andrew, hello and good'ay from southern Co.
Looks to me you have a bug problem, probably aphids, and soil that appears too wet (maybe)??? I've never been Down Under, and on a completely unrelated subject my workleader is going to vacation a whole month there, so I expect relations between our two great nations to take a serious hit, but, back to your more immediate problem- I've always assumed Australia to be dry and arid, like where I live, these conditions are perfect for peppers as long as a nice protective layer of mulch around the root system is living with it. And keep in mind that they are a lot like tomatoes where the more air that passes between your plantings the better.
Anyhow, good gardening, good luck and long live Akubra- the best hatters in the world!