It's the freedom of information act that's relevant
http://www.direct.gov.uk/en/Governmentc ... DG_4003239
In a nutshell it's a requirement that a company must release all data they hold on an individual to the individual
As far as I've ever interacted with it the DPA is about what informations companies can store and what they are allowed to publish to "unrelated" parties. Most of which appears to be completely ignored as it seems every company oin the entire world knows when my car insurance is due for renewal
As for how you right a wrong, I don't think there's a guaranteed route. Credit ratings are notorious for this
So while you can find out that a company has incorrect records under the freedom of info act there's no equivalent Accuracy of Info act to make them correct it