Ive had a BT Youview Box for just over a month now and the picture and sound are out of sync by about half a second. Some channels are worse than others.
The terrostrial channels are not as bad as the internet channels (ie. Comedy Central, Discovery) with some programmes been out of sync by about 1 second. Very noticable when watching Friends for example.
In my case the sound is ahead of the image. Ive tried altering the setting which changes the sync in milliseconds but this only gives you the option to bring the sound forward, not backwards...
In my previous home I was using Virgin Media, which I didn't have a problem at all so its most likely the Youview Box.
Also, Im not using any extra speakers just the standard ones on the TV
Does anyone have any other suggestions I could try?