Credit File Clean Up - what address do I send the letter to?

I was discharged a month ago and am now in the process of cleaning up my credit file.

I have all of my account numbers and creditors letters typed up with bankruptcy order and notice of discharge ready to go.

I have tried Googling "[creditor name] data controller officer address, but have not had much luck.

Do I just need to send it to their customer services or to a particular address/department?