An older couple I know (very late 70s) have stashed about £1500 worth of £20 notes in their house. If they bank them they will go over the savings limit for the extremely tiny amount of benefits they get, so in a way I don't blame them - but that's a whole other thread.
However, they now need to get rid of them in a world that largely doesn't accept cash and they don't go anywhere to spend them. They get their shopping delivered, organised by a relative, I think they pay the relative by cheque as the relative doesn't want to accept the paper notes because in their words it would be money laundering.
They don't spend a lot, they have no needs in terms of clothes or anything else. They don't need a cleaner, yet. They both get their hair cut at home every couple of months and probably pay their hairdresser £40 cash if that.
Wwyd if you wanted to help them switch these paper notes for plastic? We don't live nearby so it's not easy.