Have a look
here and follow the link to "Getting Broadband" then "Find a Supplier" then click on the "Full Listing" tab.
That will give you the current list of UK suppliers. You then have the unenviable task of comparing the offerings.
I found a supplier that I consider to be very reliable and responsive that way. Been with them for almost two years now since transferring from the mighty AOL. Much less stressful
ST