attached by it's buoyant polystyrene-like float to the remains of a Velella velella (By-the-wind sailor)
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Yes - and now I have located my own Velella velella.
You have quite a few postings that are tagged as Coastal and could, maybe should, be Marine too.
Lat/Lng: 51.5708, -4.2894
OS grid ref: SS414882