I did exactly this on my superhub 2 and turns out my teenager is one step ahead, when I'm not in he simply puts a pin in the reset button at the back on the router and basically wipes all of restrictions and as the standard password for this router is "changeme" he logs onto the router to get the access password! Found out that the new hub 3 has better security to stop him doing this but..... The hub 3 does not support the restrictions!!! One step forward two back I think!
I've just tried it and it and as well as being awkward to know which device is what, it ended up blocking access completely to my son's pc. He even restarted the pc as he thought the problem was with that! I still want to set it up as he spends too much time on there but how can I get it to work??