I've now got xrandr installed and can alter the screen resolution and the Hz (choice of 75Hz, 60Hz or auto. Seems odd this can't be done in Display as used to be the case for 11.04 but there we are.) It's already on 60Hz, I find. If this doesn't work, I think it's new graphics card time. Recommendations? (Not spending £400 on one if that is the case though. Nearer £40. Ideally £30.)
Bev.