Credit rating agencies are barred from blacklisting addresses. They can only blacklist individuals. However they can block credit for one person at an address if another person, at the same address has a poor credit rating AND they believe that there is a 'financial association' between the two people.
So, for example, they could refuse credit to resident 'B', on the basis of resident 'A's poor credit history, if they believed that the two people were living together as sexual partners.
If a mistake occurs (or is likely to occur), a 'notice of disassociation' can be filed with each of the credit reference agencies. (In practice, it's probably only necessary to file a notice with one of the agencies, as they usually share such information). Once such a notice has been filed, the agencies are barred from linking the finances of the two people (unless they've got good grounds for believing that the notice was submitted fraudulently). The UK's main agencies are Experian, Equifax and CallCredit.
Chris