Hi there,
Is your tv an older 4:3 screen or is it a new widescreen?
If its a 4:3 screen then there is a setting on the Sky digibox to switch the output to 16:9 or 4:3 L or 4:3.
16:9 will give you tall thin people (the picture is the wrong shape for the screen.
4:3 L will give you people the right shape but with a black bar top and bottom of the screen.
4:3 will give the right shape but with no black bar top or bottom, but bits missing from the sides esp captions etc.