Thanks for the comments Trevor - much appreciated, I usually keep to 5 minute subs because of the blooming on bright stars. I know it can be managed with software but I find most packages are not particularly good at removing blooms, (I use CCDStack). I'm on the outskirts of Bathurst so there is minor light pollution to deal with, particularly to the east.
I've also had installed, a infrared sensor to determine when the scope is parked so that I can automatically have the roof closed. On some of my later images, I suspect this is contributing a bit of noise as it is the equivalent of a searchlight at the far red end of the spectrum
Cheers
Lars