Not a bad first light image Dave,
Were any calibration frames used for the image?
I'll assume that due to the fact you're in Sydney, you're battling a bit of light polution too - which makes the colour balance you've achieved quite impressive!
You've achieved great amounts of detail throughout also!
A couple of things I'd focus on for next time would be
1. Grab some shorter subs to retain as much detail in the core as possible, you've done a reasonably good job of taiming it down with 3 min subs, for sure. I would typically do a set of ~30s subs just to get the central hot core area sorted, then blend that result right into the burnt areas.
2. There are a number of tools to help level out a gradient in images, and I think that would help to equalise the background in this image.
3. Calibration. I'm unsure if you've used darks here, though I'd say by the lack of amp glow in the top right, I'd say you did do darks. I'm assuming, however, that you didn't do flats.
While there are software solutions to gradients, don't skip out on flats with intentions of correcting it in post processing. Flats will certainly improve the situation dramatically with gradients, vignetting and normalising the background adu counts.
Can't wait to see what you do next!