Searching google turned up this thread:
http://www.iceinspace.com.au/forum/a...p/t-80648.html
There is a post by Terry B saying that anti blooming ccds like mine tend to need a much lower exposure. I've been aiming for 80% full well average in the centre 100x100 square. I think my flat frame exposures are too long.
Since it's cloudy again and everything is set up as it was, I'll give it a test tonight.
Edit: Set maximum to 9000 and still the same. Le sigh.