Some of the graininess might be small stars too. The graininess is not uniform across the frame. Was looking at a photo from another site showing hundreds of faint stars across the image. The pattern of the darker regions matched that from our image.
Here is a link to a superb photo from another IIS member Marcus showing just how many stars there are in the region:
http://www.pbase.com/gailmarc/image/78651501
I think the old timers is catching up. Autoguiders work better with a scope to autoguide through. Better to remind myself of that now than at Lostock.
Cheers
David