If We Say "Superfast and Unlimited" Well, 'Superfast' Means What We Decide It Means, and 'unlimited'

means 'of course we do apply limits' ... is the conclusion you might reach after reading this in the Register

Not that the ASA can prevent EE doing whatever it likes. The self-regulatory body has no teeth and just makes recommendations, though these are generally respected if only for fear that it will be replaced by a proper regulator.