Someone I know has a 58db line and rubbish service from Orange: would LLU help him (TalkTalk is an option) ? Also, do you have to give up your BT line and riska future £140+ reconnection fee ?
LLU isn't going to change the line attenuation to anything significantly different from the above.
I would rather hack off my testicles with a spoon than join TalkTalk/Tiscali/CPW.