Likely UK birds (mainly juveniles?) dispersing south and concentrating birds together close to the coast as a weather front/cloud/wind moved from south west.

Excellent! The first in 2023 and then Yorkshire records just got into double figures last year in total, but I'm still waiting in my East Yorkshire garden. They are on the way.......

Clifden Nonpareil

Yes, I think you are right. The back is not long enough for Sei. No large blow seen, just sparse weak blows. No impression of larger size. Thanks... interesting discussion!

The middle right image is the same individual and here's another similar shot. You can see the blow hole and dorsal together here. Longer backed? not sure in this image. Dorsal I agree looks good for Sei. The Minkes were definitely blowing quite a lot but still weak sparse blows.

Definitely not a stupid question. I agree it does look quite like Sei. No, couldn't rule it out. Difficult at distance. You may be right? Not sure if someone with more knowledge could tell from the images?