Display wrong after update today.

I have been away for 10 days and on my return today I did an update which included kernel 3.6.9 PAE and a grub2 update amongst others. After rebooting to the new kernel I find my display which was working previously now comes up with desktop not aligned, it starts in the middle of my display and wraps around, ie shifted about 50% to the right (if that explains it - I'm not sure). Anyway setting display options in settings and rebooting does not fix it, however rebooting to kernel 3.6.8 PAE does return my desktop to normal. I use an ATI gfx card with the free drivers and normally it displays my desktop in 1920x1080 OK but the new kernel sets the display to the same dimensions and sync but shifted and wrapped!

Anyone any ideas please?

Stuart