Two immature gulls both large white headed. Both sets of images taken today.
Gull 1 juvenile marinus or argentatus? (or something else)
Gull 2 Might simply be argenteus perhaps it's been a long day but I seem to be seeing some cachinnans features but not others.
Small white head, streaking on hind-neck, dark centred tertials with pale edging not reaching the coverts. Four distinct wing bars on the open wing but then it also seems to have a pale-ish panel on the inner primaries ruling it all out. The tail band is quite narrow too. Is that a whitish wedge running up the back or just a product of the bodyshape as it takes off? The moult on the scaps appears to be advanced, Are the legs long (look at image 1)? It also appears to have a slight sagging hind belly. But then i don't think the primaries look particularly long. Apologies for the quality of the images, they are cropped due to the distance at both sites. In the first image of the second set the gull in question is to the left in the foreground not the argenteus preening or the older bird in the top right.