Neil MacGillivray: A pension death benefit claim quandary

I was recently faced with the following conundrum, and what follows is just a ‘brain dump' of me trying to think through how such a situation might play out. The situation was that an adviser's client had died and through their expression of wish had nominated three beneficiaries of their self-invested personal pension (SIPP). Two of the beneficiaries had intimated that they'd like to take the lump sum death benefit (LSDB) option, whereas the third beneficiary was refusing to engage with anyone, to the extent that the adviser felt they may never do so. For simplicity, I'll call them A...