Help! Cant get a mortgage because of tenants

Hi all. I'm having a nightmare at the minute trying to get a mortgage. I am trying to go onto my wife's mortgage & consolidate the unsecured debt we have. The problem I'm having is that I had a rental property a few years ago that had tenants in. The gas/electricity bill was not in my name (it was in the tenants name as they were liable for the payment). To cut a long story short, the tenants did not pay the bill & vacated the property one night. Since then, the energy supplier has registered adverse history in MY name at this address. This is showing as still active (I've not lived there for 6yrs and sold the property 2 1/2yrs ago!)

This has stopped me getting a mortgage. What can I do and should it be registered against me?

Thanks, in advance.