Pension part 2

Not sure what you have got but if you have got a letter inviting you to apply for your pension do it online. I don’t know why they would need your marriage certificate unless you are a widow? And claiming widows pension? If that is the case, send all certificates registered post (take copies if you can). Not saying they won’t go astray but unlikely and if you have proof of postage you will get reimbursed for replacements.

It’s easy to get a new marriage certificate if required and not expensive.

I didn't have to send my marriage certificate for my state pension but was asked to along with my birth certificate for my private one, as we were in lockdown I totally refused to do it and told them to find another way, was told I could get a copy verified by my bank or a solicitor, banks were not doing face to face so asked a solicitor to do it, no problem apparently its something they do all the time, they photocopied it and signed and stamped it and it was
accepted by the pension provider

It's so long ago that my memory might be wrong but I think I had to supply a copy of my divorce decree absolute and my ex's national insurance number which he was quite reluctant to give me.