Any help would be really appreciated. Thank you.

Sunshine is self fertile but better fruit set and bigger fruit will result from pollination. Dont know what kind of water you got in Aust. but if you can collect rain water in trash can your plant will be happier. Takes the guess work out dealing with Ph swings in potting soil. I usually have a 2 to 3 inch covering of pine bark mulch on my potted plants. What I like to do is stick my finger through the mulch down to the soil and if its wet, dont water, if its moist water the next morning. Thats how I swing it during the fall, winter, and spring but once temps start reaching to 90 degrees F they can be watered every day if out in full sun. Here in Houston the summers hit well over 100 degrees and if you dont water daily things go down hill fast. Small pots can be watered twice a day in that kind of heat. The main thing is you dont want the soil to ever dry out between watering. It must stay moist at the very least. What kind of soil did you plant it in?

It is true that Sunshine Blue will bear fruit without another variety around, but the berries will be small. I was amazed at the difference in size once I had another variety present.

I have gone through the "brown leaves" syndrome several times with my plants. I'm guessing it's not enough water/too much heat. That's what the problem was with mine. If you have a particularly hot climate or even a string of very hot days, partial shade would be welcome.

It's not that hard to keep a potted blueberry shrub watered, so I suspect that this is not the source of the problem. You don't mention the pH of your soil or water, so I am guessing that you might not know what pH is, how it is measured, and how it can be controlled. Unless you have naturally acidic soil, and neutral or slightly acidic irrigation water, it is necessary to learn about pH when growing blueberries, azaleas, rhododendrons, and other plants that are adversely affected by alkaline soil.