As I said, there is a REMOTE possibility that she is entitled to a state pension in her own right. The only other possibility is an occupational pension (which is more likely to the reference to PoL rather than LC.
As I also said - the stamp is no longer required. You obviously didn't believe my post so I will try and find the DWP reference point......this to keep you going:-
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No, a stamp is not required for a Department for Work and Pensions (DWP) life certificate in the UK. However, you will need to have the form signed by a witness.
Explanation
A life certificate is a form that the DWP sends to people who live outside the UK to confirm they are still eligible for a UK State Pension.
You should return the form as soon as possible.
If you don't return the form, your payments may be suspended.
You should follow the instructions on the form, including who can sign as a witness.
You can provide a document with your photograph, such as a passport, national identity card, or driving license, to the person witnessing your declaration.