My sky box is on wifiUnless you can have the box where your pre installed Ethernet cable is, you won't be able to use that one.
My internet box sits on top of my sky box its that small, I used the Ethernet cable which was in the back of my sky box ( from the router ) and plugged this into the back of my internet box. You then need an Hdmi cable from the Internet box to your tv, or use the Same one the sky box uses?!?
My TV isn't on anything
The Ethernet cable is in TV corner
Wouldn't I just plug Ethernet cable into this mystical new box and then HDMI from now to TV ?
( you can see why I haven't bothered before!)