In reply to Rog Wilko:
Yes. Did the night time Mousa Broch experience on Shetland a few years back.
I've also had plenty of good views from the Western Isles ferry. Last year there were lots around the Hawes Bank shallows north of Coll. Also saw a few Leach's Petrels in Village Bay on a trip to St Kilda.
I'm also hoping to get down to the Scilly Isles sometime in the next few years for a trip with Scilly Pelagics. They seem to have quite a bit of success with seeing Wilson's Petrel, a tiny southern hemisphere species which can be found off the west of the UK during our summer.
Hard to imagine birds smaller than a Blackbird living most of their (often quite long) lives out on the open sea.