Hi All, we've recently had new windows fitted and after cleaning them last week discovered that the internal side of the double glazing i.e. the panes that face inwards to each other, the ones that you cannot touch, has dust and very large areas of marks all over them, including one long line running across the middle of the pane. You can't see it on an overcast day, but when the sun is shining on them at a certain angle (which it was every afternoon last week - after the window cleaner had been too) it looks horrendous. This shouldn't be the case should it?