Getting the right power supply or PSU as they are known shouldn't be that difficult yet there are so many copies out there it can be a minefield.

At AdmireIT we have the Official supplied BT Power Supplies and always test prior to shipping so that you know you'll receive a working power supply that is compatible with your equipment and more importantly has passed the rigorous safety tests that all CE Approved UK Power Supplies demand.

We stock many models of router Power Supplies and Youview Power Supplies, so hopefully we carry the one you're looking for

A small snapshot is below and available on our store here

BT Complete WiFi Disc Power Supply 12V 2A

BT Home Hub 4 Type A and Type B PSU

BT Home Hub 5 Type A and Type B Power Supply

BT Smart Hub Type A PSU also works with BT Business Smart Hub Type A Power Supply

BT Smart Hub 2 Type A  PSU

BT Youview DB-T2200 Non-Recordable Power Supply 12V 1A

BT Youview+ or BT Ultra HD UHD Power Supply

BT TV Box Pro 12V 2A Power Supply PSU

Finally testing, a simple test can be performed with a multi-meter, turn the dial to 20V, plug in the power supply, put the positive on the outer exposed silver part of the power supply connector and then put the negative inside the connector. Then take a look at the reading it should show around 12 Volts.

A useful video on how to do this is here