First of One wrote:

Probably not the answer you wanted, but the easiest solution is to use a
different screensaver, something 2D like flying windows or blank screen.
Remember, the screensaver activates when you are NOT using the computer -
there's no point in showing a pretty picture.

It does the same with some other screensavers too sadly. I've found one that
works ok now. Odd though. Any ideas why ?

Graham