I'm in the same boat with Telewest. I don't leech porn or illegal files so I don't really have a need for any faster speed, but web pages are jam-packed with garbage now to justify the existence of 1\2\4Mb lines and it's becoming impossible again to do some of the basics.
That said, I do manage 28-32kbps so it does appear you have an issue you may like to take up with Telewest (I'm not in a Eurobell area myself).
You may want to look at click here and make a complaint in the newsgroup blueyonder.feedback where they will studiously treat you with contempt and tell you Telewest is not a charity. At the same time they will ignore the charity element of 512\1\2Mb users being provided with free, unrequested 50% speed increases twice within just a couple of months.
You aren't the first, nor will you be the last. But you are completely in the right.
Hopefully, the recently announced doubling of speeds by BT will knock them out of their complacency and force them to make the entry level 300k or 384k, just so we can tolerate the garbage on the internet at the same rate as we did when 256k was a reasonable service. Something that seems a very long time ago now.