Found 21st Dec 2017
Seems Game have some overstock of the Steam Link. You can reserve and collect from store. Checked Leeds, Newcastle and London who all have stock...somewhere.
Stream your games to your TV with Steam Link
Setup is easy. Just connect your Steam Link to your TV and home network, where it will automatically discover any computer running Steam. All that’s left to do is grab your favorite controller, kick back, and enjoy your collection of games from the comfort of your couch.
Steam Link is designed to take advantage of the horsepower you already have in your home, streaming from your current gaming computer by mirroring its experience to your TV. Video and audio data is sent from your computer to the Steam Link, while your controller input is sent back in real time. Virtually every game that your computer runs can be played on your TV using Steam Link.