I think BT need to issue a lot more guidance for people in this position. When you say two landlines do you mean two telephone numbers (but on the same BT account)?
I don't think BT realise how much of us have legacy lines eg my switch over tomorrow is the following set up - two telephone numbers on the same account. One line just has broadband on it with one telephone number - number not used for calls and another telephone line/number which is the home landline which has NO broadband on it.
I am assuming that the broadband telephone line continues with no changes at all using the old hub (not the newhub2 which has come) and has nothing to do with the landline only line which brings telephone over copper wires to that landline telephone and that I plug the new Hub2 into the master socket for that landline number and that BT provide a basic service on that on changeover day tomorrow so that that line continues to have telephone calls with landline plugged in back of new hub and that the second telephone number on that account continues just to run the broadband on the old modem unaffected by the fact we have those 2 lines from the legacy days of people having different lines. We had a line for calls in dial up old days and line for internet for example (and much else which I won't complicate with on here).
By the way AI I think wrongly told me BT would do the logical thing of keeping the landline number and somehow moving it over to the broadband line but I don't think that is correct at all so am ignoring it for now and seeing what happens tomorrow when I am notified DV is turned up and I will plug the new Hube 2 into the landline master socket up by the ceiling in the garage at other end of house.
If I am wrong and you have one telephone number / line on your bills then your question is just about extensions which is a different issue.
