I'm glad you have got the audio sorted.

I don't have a Sky+ so I can't help you with what controls the aspect ratio of the S-video output.

As a quick test do you have a TV with an S-video input to check that it is OK?

Is the picture with the bars on the side of the correct aspect ratio or is it squeezed?

Are there separate controls for aspect ratio for the digital and analogue sides of the card?