I have a plethora of BA items... Including 2 CW blankets for the exact purpose of picnics/park laying...

Quite often, well a couple of times a year, BA will have a "Catering Sale" for staff, where they sell off excess or unwanted service items. They can range from odd bits of First crockery (of which I have several), blankets (of which I have 2 x CW), galley equipment (1 large serving spoon (great for baking) and the matching large serving fork), 30 Club Europe linen table cloths (make great napkins (now not part of the CE service)) and a few other odds and ends.

They usually sell things for a few pennies to a few pounds, and the money goes to Flying Start or Dreamflight etc...

So, depending where on the south coast (near Brighton...?) this was, it may have been a crew member who has bought stuff like this etc...