Little Shearwater - presumed Barolo's moved south at 0545hrs with Manxies and fed for a short time before moving off slowly south again with the Manx Shearwaters. Despite looking really hard for the whitish/silvery greater covert patch there was no sign of it, that part of the wing was uniformly black with rest of wing, notes here:
Sadly no one present at the time to share the sighting with.
Other birds from 0515 -10.30: 1140 Manx Shearwaters, 1 Baleric Shearwater, 1 Sooty Shearwater, 5 Storm Petrels, 2 Pomarine Skuas including close 3rd cal year bird, 3 Arctic Skuas, 1 Bonxie and 29 Puffins. Also 1 Ocean Sunfish and at least 2 Harbour Porpoises.
Update: Fascinating link from Chris Townend: http://peteralfreybirdingnotebook.blogspot.co.uk/2010/05/barolos-marconesian-shearwater.html