Lost Deeds Santander

My son is in the process of buying his first home here in Belfast. All seemed to be going well until his solicitor informed him that the deeds to the house he was buying were part of the ones held for "safe keeping" by Bradford and Bingley that were lost in a fire at their deeds storage depot. The same Bradford and Bingley who in turn was bought by Santander. Which is the mortgage company he is using to buy the house.

The problem is that the house in question has had two previous sales that have fell through and it seems that this happened because of this deeds situation. Recently he was informed that Santander are in the process of sending his application back to the underwriters to review the mortgage application and his mortgage advisor told him it was because of the deeds not being available. Which seems strange when one considers that Santander actually are now responsible for Bradford and Bingley's actions.

So I was wondering if anyone on this forum can give me some information that might help to clear this up. Any information would be greatly appreciated by bot him and me. Thanks in advance for any help.