hm, those very pink legs are worrying. i'm more inclined to call it an advanced 3cy herring gull, anyhow a dark and abnormal plumaged bird. isn't it possible for herring gulls to show a grey MC bar right now? well, mantle seems very dark and head shape is square but i don't give much on that since all male large gulls can have square heads when relaxed. how was the iris colour? apical spots should be there in a normal 3cy YLG too (smalller and often worn off at this time of year, largest in p3-4)).
this ind. generally looks very worn.
and that's surely the male type 2cy casp to the right if it