Broadband based on the BTw IPstream product (most ADSL) can be very frustrating and often slow because of the prices charged by BTw for backhaul from the exchange to the ISP (cost of renting the large endpoint routers where many individual customers get consolidated). If there is an LLU presence at the exchange it normally represents better value. Look for Be/O2 or Sky LLU at your exchange -
http://www.samknows.com/broadband/search.php
If you can't get either of those then do some research elsewhere on the best provider for you as it is not likely to be Virgin National.