Here they are reversed, the right one in image 1 is on the left now and they seem to be the same.Looking again at the yellow-billed individual at 500% you can actually see quite obvious see the white frontal patch, not reaching behind the eye but not with the straight upper edge in a similar fashion to these:
But notice this Little taken in Greece:
Itīs a little more difficult to see this in the dark-billed bird, which is still much in winter plumage (2cy?) and clearly with 4 dark outer primaries which indicates Saunderīs.
Maybe showing to much unsurity but still not 100% Adrian.