Just my thoughts, but how can they reissue a 'new' default notice, this is purely fiction ? And you no longer have any agreement with them ? You might be interested in reading this - http://www.consumeractiongroup.co.uk/forum/showthread.php?170345-A-Tale-of-a-Dodgy-DN

I didn't have my account number - I took out a loan with HFC BANK in 1991 - phones them and said I thought I had an account, gave them the address that i thought it was registered at. They then asked me some questions like which branch j took it out at, where I worked at the time I took it out, and my job title at the time. They found me fairly quickly and confirmed the account numbers in writing with copies of the agreements about ten days later