Looks a bit noisy for two and a half hours Beren, I would have expected a lot smoother image for that length exposure. Tracking and guiding looks good, not too sure about focus.
It also looks as if you have some small specs of dirt on your chip. They can be cleaned with isopropyl alcohol ( Dick Smith Electronics ) and cotton buds .... read your camera manual for details, although it's not very helpful. Another option is to subtract flats from your images. You can find tutorials about this on IIS and other sources.
The main thing is that you are getting out there and practising your skills and the more you do it the better you will get.
p.s. I just adjusted your image a little. Removed gradient, gaussian blurr layer, levels adjust. Only slight changes ... hope you like it ! Can't work miracles with small jpegs.
