but try to remember that when BT wholesale tell you that they can't provide you with certain information because of the data protection regulations they aren't inventing that as a reason. You aren't their customer - your ISP is, and they have obligations to the ISP under the terms of the act.
The other thing to bear in mind is that BT are under no legal obligation to provide you with a data quality phone line - their contract with you is to provide you with an analogue voice-quality only. This isn't something that falls within the orbit of BT wholesale anyway - they are there purely to sell ADSL services to ISPs.
Of course we can all think of ways to streamline the system, but that's because we don't have to maintain and run a national telephone that has its origins way back in the early part of the last century. By and large I think BT do a pretty good job, but of course there are problems with ADSL and line length. BT research engineers have been actively researching the line length problem, and we shall be seeing an increase in the radius dimension for home users, although this might be at the expense of downstream speeds.