I find it ridiculous that I can't watch my BT Sport Channels via my You View box in a different room when the TV connected to the Sky box is being used to watch something else!
Therefore I need to know how to remove my sky box viewing card registration so that I can watch the BT sport in the other room.
BT will only allow you one subscription unless you pay for extra box on either Sky or BT.
Try this link
You may need to phone BT to transfer BT Sport from Sky to Youview Box.