MSE News: Are you financially attractive?

I recently had card rate taken down by a sub prime credit card company - I am not sure I am the tastiest proposal though!!

An online retailer lets me pay 14 days after delivery now they have brought in Klarna! Which feels like a form of credit entrustment without the hassle and is a very big step forward in abolishing what may have caused credit needs? So I think it's amazing.

I can certainly attest to the importance of checking credit files regularly. This week I tried to get an AiP from my bank, having found a property I would like to offer on...although I checked my score a couple of years ago and everything was fine, when my mortgage advisor ran the necessary checks, he identified a problem with my credit file!
I checked online with Experian and it looked perfect...but for the fact Bradford & Bingley/Mortgage Express had failed to close down my old mortgage account when they sold it to Chaconia Mortgages in May 2015. I sold this property in July 2015 and Chaconia mortgages closed their record with the necessary credit reference agencies.
Experian advised to get in touch with Bradford & Bingley, who won’t do anything until they receive written confirmation from Chaconia Mortgages (whose administrator is Engage Credit) and won't ask for this themselves. I can't see what responsibility Chaconia Mortgages has to provide written confirmation when they were sold the mortgage outright? Surely Bradford & Bingley should have closed the mortgage when they sold it on to pay their debts?! (They obviously had to keep records on file for a certain amount of time, just in case this was needed by Chaconia Mortgages, but surely this shouldn’t have prevented them closing the mortgage?)
Do I have any redress against B&B, since their error has adversely affected my credit rating/ impeded the purchase of a new property until they can rectify the status on my credit file?