CRF Clean up - Santander Issue

Hi all,
I went bankrupt in April 2008 and have spent the last 2 years (on and off) cleaning up my credit file.

I'm almost there except for Santander.

I had a joint current account with Alliance & Leicester (which belongs to the Santander group).

I included the current account in section 5 of my bankruptcy petition (which had an overdrawn balance of £600).
Myself and my partner separated before my bankruptcy but I know they went bankrupt in June 2008 (2 months after me).
After trying to get Santander to correct the entry (they are showing late payments for the end of 2008 and start of 2009) with the overdrawn balance - I then decided to raise queries with Equifax and Experian.

Equifax have come back to me and said that they contacted Santander and they said it wasn't part of my bankruptcy. I also sent copies of my bankruptcy order and discharge certificate. They told equifax I had to contact them directly.

I've contacted them on 3 occasions in the last 9 days and the latest call they told me (collections and recoveries department) that the information is correct. They said it's likely to be because they haven't received my ex's bankruptcy details.

I'm no longer in contact with the ex - the point of the matter (correct me if I am wrong) is that I did put the account in the bankruptcy petition, all debts that existed up to my bankruptcy should be included and Santander are obliged by law to date anything up to (and not after) my bankruptcy date.

Can someone advise please and how I can correct this.

Many thanks.