Belated news, I'm afraid (phone battery died). I finally succumbed and made my first visit to Preston Down. It took me 24 years to finally see an adult Brown Hairstreak in Devon ... and like buses, three came within half an hour!
Decided to have a look at the sea off Berry Head, though it was rather murky at sea. While I was there, from 15:00-16:50, there were Manx Shearwaters feeding offshore - something I don't recall ever seeing off the Devon coast. The best scan count was 112, but some seemed to be moving through. Up to six Balearics were with them most of the time, plus 7 Arctic Skuas. Also briefly a juv skua flying and behaving like a Long-tailed, feeding with some distant shearwaters, but I lost it in the murk.