I asked the question firstly to a Barclays Bank Worker:
"Visit a branch.
There is a tool available through Customer System/Customer Gateway (they may have to specify this, the person will likely not know what they're looking for - it's rarely used) called "Migrated Account Enquiry."
If they enquire on the Barclays sort code and account number, it will provide the original Woolwich 10-8X-XX sort code and account number"
------------------------------- merged -------------------------------
And then to their customer relations manager:
"If the customer is submitting a request for copy statements, they would need to specifically mention the requirement for Woolwich statements as I believe they are processed from the account details provided. Previous Woolwich account details can be traced and provided if requested.
In terms of capturing the details of a complaint about unauthorised overdraft fees, our Customer Relations team actively looks for previous Woolwich fees that have not been subject to a previous complaint, whether or not the complainant refers to these."
"Visit a branch.
There is a tool available through Customer System/Customer Gateway (they may have to specify this, the person will likely not know what they're looking for - it's rarely used) called "Migrated Account Enquiry."
If they enquire on the Barclays sort code and account number, it will provide the original Woolwich 10-8X-XX sort code and account number"
------------------------------- merged -------------------------------
And then to their customer relations manager:
"If the customer is submitting a request for copy statements, they would need to specifically mention the requirement for Woolwich statements as I believe they are processed from the account details provided. Previous Woolwich account details can be traced and provided if requested.
In terms of capturing the details of a complaint about unauthorised overdraft fees, our Customer Relations team actively looks for previous Woolwich fees that have not been subject to a previous complaint, whether or not the complainant refers to these."