One other thing you could is abandon the landline phone and enjoy the higher speed broadband. The to get back on the phone take out a VOIP (internet phone) such as Vonage. We use one to give us a second line for my business and it works well. The cost is very reasonable at around £6 per month for 24/7 incusive calls to 01, 02 & 03 numbers. You will still have to pay BT for the line though.
One quirk of our setup is that when the underground line to house got water corrosion problems the landline phone stopped working the internet phone carried on working so we could ring the fault reprting service.
Rans6...........