A42 form request form Dwp

Hello (again) and I apologise if these questions seem silly.
I cannot locate a bank account the DWP are suggesting is mine. I suspect it’s a ppi refund that they are thinking is something else but despite giving her that paperwork she still wants statements form an account I do not own. Obviously the bank will not divulge anything about this account to me.

The compliance officer has said she will send out an A42 form but she wouldn’t/couldn’t tell me if this gives them access to all my accounts (nothing to hide but I have supplied statements for these accounts already so it’s unnecessary) she also wouldn’t/couldn’t tell me if this form allows a one off enquiry or if I have signed my bank accounts over to them for good.
I have tried googling but I’m not coming up with anything so far.
The bank are willing to write a letter to say this account does not match any I have had or currently have but this is not acceptable proof apparently.

Any advice appreciated