I finally took my original Hudl back to Tesco for a replacement. The screen issue was too much to deal with finally. Have to say they were great all the way from 'Ken' at Tech Support to the staff at my local superstore. So I now have a rinky-dink new tablet which appears to NOT have any screen issues. I also noticed that the power and volume buttons are slightly bigger and stand proud of the frame (which they didn't on my original). So it seems that there are revised models. The model number is the same in the 'About this tablet' screen but I wondered if anyone else had a newer version and whether they encountered any screen issues?
So far so good though