Juud,
Many thanks for the link and taking the time to reply so comprehensively. In this instance I don't think blame can be apportioned at check-in and certainly not to CC. Four persons were checked in together ABC&E probably without check-in staff being aware who was seated where, so seeing D&F pre assigned probably didn't ring any alarm bells.
There was a body odour element but it was a very hot day so perhaps not a lack of personal hygiene was to blame.
Fingers crossed for the inbound.
May your single malt have the desired effect.