I'm going to attempt to keep this concise to avoid confusion.
Background: DP's father passed away in 2013, DP and his dad were not close, his dad split up from DMIL when DP was small, remarried, no further children, then divorced. No further significant partners or relationships at the time when he died. DP had a sister who passed away in her early twenties before dad, no other siblings.
When he died dad was in his late 50's and it was unexpected, DP dealt with everything at the time, closed the accounts he was aware of, sorted house to give back to landlord and organised funeral. Dad didn't have much in the way of money and DP had to use his own savings for the funeral.
Fast forward 8 years, a couple of months ago DP receives a letter out of the blue from a pension provider explaining that they are trying to find his dad's personal reps as they have been made aware by DWP that he has passed away and there is a policy with them. We complete forms and return back. More forms arrive asking for details of children, marriages, death certificate etc. Again we complete and send back. They have now contacted again to ask us to provide the previous addresses for dad. We have no idea, DP hadn't seen his dad for a number of years before he died and their contact was very limited and at times nonexistent.
Is there any way we can find his dad's previous addresses? I have tried an electoral roll search but cannot seem to find anything even though his name was very unique, I have even used a paid for search but that also returned no results.
I appreciate the pension provider needs to be thorough in their checks but if we genuinely cannot get this information can they refuse to pay out to DP who is now the only heir to any of the estate?