CCJ not known about

kaMelo

Get the earliest bank statement you can get, it's short but only by four months. In combination with an EE bill, council tax/electoral register, driving licence, payslips/training courses or whatever else you were doing six and half years ago that may have your address upon it would be a package of evidence difficult for them to dismiss.
Also I note you said you lived somewhere else a few years ago to which they have sent letters to. Has any CRA got any record of this address and when you moved to where you currently are? I only ask as I notice Equifax still has my previous address listed and I moved from there in 2002.. 

As a side note, I know it's a bit of shutting the gate after the horse has bolted and certainly not meant as a dig in any way, more a heads up to anyone else that this is a good example of why it's always a good idea to download and keep a copy of all documents or statements. They take up very little space, providers don't keep them forever and you just never know.

joebloggs11

Update:

Been in Halifax branch today and got the bank statement for the specified dates and also been on the phone to EE and they’re sending me the bill out so seem to be making progress albeit very slowly. 

Robbie64

Are you on the electoral register? If so you will have information about this on your credit file including the date you first went on to the register for your address. If it is the same address as now your previous address and details may also be listed.

joebloggs11

Yes always been on electoral register but they’ve said this isn’t enough proof so I’ve sent them bank statement so hopefully will hear from them this week