I don't recognise the white neck band; maybe someone can, even though a poor photograph. This was also flying over the cliff and chine.
No interactions present.
Swifts are birds of the high Summer, they don't like our April wintery
showers. Sand Martins, however, I have watched feeding whilst in the
middle of a mid March snowstorm. This looks very much like a Sand
Martin to me.
Thanks. They have been seen at Hengistbury Head and I have looked for their excavations on the local cliffs.
Lat/Lng: 50.72053, -1.84667
OS grid ref: SZ109912