Thankyou everyone for your responses. Last night I got out and took some more hydrogen alpha images and I combined them all to make this image. The noise in the previous attempt is vastly reduced, I think this is now my best image. Again I could test the pointing of my new belt driven mount and I was not disappointed, it will make creating these long images that much easyer.
This is 280 minutes ha with 60 o3 and 60 s2
Link to larger image :
http://www.astrobin.com/full/28455/?mod=none