[Sephiroth]

Thing is - I can't see what they can do with your existing cable to the street cab. One could imagine pulling a "better" quiality cable with lower loss, but chances are you've got good enough cable anyway. A test with special eqquipment would quickly determine your chances there.

One could also imagine some sort of amplification at the street cab - if it has power; although that isn't best practice since amplification should be further down the line.

You do need to put VM on the spot to determine your case fairly.

Are you a long way from your BT exchange? You can see what I'm thinking in case VM don't want to sort this out.