What's the birdie?

Silverknowes again, and although I'm pretty good with birds I didn't recognise these. A flock of over 50 small wading birds... Perhaps a type of plover or turnstone?
They were not much bigger than a Blackbird and had a mainly brown upper with bands on the wing body with a white underbody, when they flew there was a clear dark and white band on their wings. Orange legs and black /brown beak.
Only had my phone, so couldn't get a good shot, any suggestions?
A purring / chirp type of call. I've put an extra but not a great shot. I got the impression that a large proportion were young, so perhaps, just begun a migration.