Very much less than ideal conditions at the moment - slow moving patchy cloud, half moon.
However, at 1600 ISO and using a cable release plus a tripod for 30s exposure at f3.5 the first image is promising. Comet Holmes is easily visible.
Here's the same image, crudely processed in Photoshop to adjust the levels.
Levels adjusted in Photoshop
Looking forward to doing some longer, tracked exposures (as soon as I can bodge a platform for the camera on top of my telescope equatorial tripod).