Suitable / unsuitable phone line, what's going on ?

Hi all, I am still thinking about changing ISP (see earlier query on
Eclipse) and up to last week, whenever I was doing checks on the sort of
speed my phone line could theoretically get up to by entering my number
on ISP's websites, the results were 6.5M.

Pipex apparently carried out some work on my exchange this last monday
and since then, my line according to some is unsuitable for broadband !

I have called BT who are telling me that contrary to what their and
Eclipse's website reports, there nothing installed on my line that would
prevent me getting broadband (I should think so since I am currently
connected !).

This is the sort of results I get.
From Eclipse (BT reports something along the same lines);
We have detected a feature or service on your line that is incompatible
with Broadband. Your line maybe a 30k loop, private circuits, RedCare,
Meter Pulse or a PBX extension line. You will either have to ask BT to
remove this feature or choose another line...

From Pipex, my current ISP !!!
Your exchange does not support Broadband

Sorry - BT have not yet upgraded your line/exchange to allow broadband.
If you'd like to try Pipex dial-up internet access please click here.

And finally from Zen;
Your exchange is ADSL enabled, and our initial test on your line
indicates that your line should be able to have an ADSL broadband
service that provides a line rate up to 2Mbps. Our test also indicates
that your line should be able to support a potential ADSL Max broadband
line rate of 6.5Mbps up to 8Mbps.