On some digital channels (Five, BBC4 are the ones I've noticed) a letterbox picture is stretched upward so that it reaches the top/bottom of the screen and the sides are trimmed to fit a 4:3 regular picture - whatever the setting on the TV. Analogue on Five is fine. Calling 151 got the suggestion that i alter the widescreen setting on the STB, but no use - 151 then baffled.
Any cures, workarounds, or other information, anyone?