narrow vertical bars on Toshiba 50wt29

I have just taken delivery of the above and find the picture superb apart from one niggle.On the extreme left of the screen there are two narrow transparent ,slightly curved bars .These are most noticeable on night scenes.The Harry Potter DVD at the beginning is a good example.They are stationary at all times and are present on all sources.This gives the effect of a slightly lighter shade when the picture is coming through with a very dark scene.Any ideas what would be causing this? Thanks.Charles