If speedtest.net says he's connected with Talktalk, he's connected with Talktalk.
OK let me spell it out seeing as you missed it "hello Talk Talk, can you tell me why my BT wireless modem is working giving me my internet connection from you" pretty basic way of investigating wouldn't you say!!
You wouldn't assume that the same device can work with two different ISPs? Have you considered reading say, RFC 1661?
Obviously whatever RFC 1661 means it doesn't apply here, but glad someone here reads that stuff so I don't have to! you must be a ball at your local!
Because newer automatically equals better. Frankly, all models of Homehub are a joke. But so is the most of the stuff Talktalk supplies, so..
That's not what I said, if both devices are going to give him the same internet speed then why not go with what his ISP gave him, and how do you know TT can do any DIAG on the BT router? simple deduction of logic TT internet TT router!!