Wow, your 50D does much better than my 1000D! This my 1000D At the same ISO, but 10s exposure:
http://farm3.static.flickr.com/2776/...80f74fc7_o.jpg
While I am also in suburban Sydney (near Strathfield, that counts right?), I appear to have much less sky glow.
I think your pictures will come out great once you stake them
It certainly improved the quality of my pictures, took away much of the noise.
GLHF.