hi, what kind of things are DLing slow? like iPlayer? or P2P, ftp, software from webstes, windows updates etc. Are you using a speedtester, if so post the URL for your test (and check the sync is still 15k at the time) or post the details here (speeds and ping)

which? is aimed at consumers. Once a consumer has chosen a company, the only real issues for consumers are how that company deals with problems. The company should in effect be transparent.
A customer with a problem is worth many thousands of customers without problems. Deal with it right and its worth thousands of happy customers, deal with it badly and thousands of happy customers don't cancel it out. Since the introduction of forums like this, these ratios have skyrocketed.

However, steveputmans comment was entirely worthless to the OP