I forgot in my earlier posting to recommend what is probably the most techie friendly UK ISP.

http://aaisp.net/

They may not be cheap, but they a very good ISP. For example, they have been particularly pro-active in identifying problems in BT's network, by pinging all of their customer's ADSL lines on a regular basis and aggregating the results to spot problem before users have even seen them. I haven't come across any other ISP who are this agressive at finding problems without the user having first to find a problem and report it.

That said, I am currently with EasyNet, who I would not recommend. I am with them because when ADSL started I wanted a 1Mb 20:1 contended line and at just over £100 a month they were the cheapest. BT have since reduced their wholesale price of ADSL by about 70%, but EasyNet have never reduced the end user price by even a penny.

I could now get 1Mb for less than half what I am being ripped of by EasyNet for.
I intend to switch to PlusNet or AAISP when I can, but BT make the migration so painful (especially since I run my own domains on the line) that I have been putting it off for nearly a year now.