Most CCD cams are far more prone to CCD smear at high shutter speeds. Your 'graininess' description doesn't sound like this though.

Tom, that might well be it, I looked at a recent case (didnt take a still this time) and there is quite a lot of blurring/smearing as well. I'd have thought a high shutter speed would have prevented this but it seems to have made it worse

CCD smear was a disastrous failing of the PDX10. I tested the camera for Computer Video magazine a few years back, and my tests showed that smear made any shutter speed faster than 1/100th sec a no-go area.

The FX1 has a 24p cinema effect (or 25 in your case). Have you tried using that? Granted it's not true 25p, but neither is what you are doing.

My videos look a lot like the screen shot you attached when I view them in Final Cut. That's why I de-interlace and/or convert to pro res. What program are you looking at and what's your codec?

Do you mean you deinterlace when exporting stills or the actual video? I only deinterlace video when slowing it down but I still manage to get quite bad jitter.
I use premiere pro cs4 and I'm unsure of codec but export as 1920x1080 mpeg2.

Thanks for the ccd smear info and pics, although I do get that it appears I can now rule that out of this issue.