Cuckmere Haven 25/11/15

An afternoon walk down both sides of the Cuckmere was rather quiet. The east side held probably two Short-eared Owls. Never seen a winter population here before so it would be good if they prolonged their stay. 

An assemblage of Gulls on the west side sent me that side where I quickly came across this bird photographed below that I strongly believe is a third-winter Caspian Gull. I've no previous experience with this age group but it certainly stood out which is key, and other features mentioned below are also pro Caspian. Any comments very welcome.

The bill stood out more than anything being a dull yellow/green tinged colour with a dark sub-terminal band spreading on both mandibles. 

Long sloping forehead, all white head appearing pear shaped. All black eye. Longish gape line. 

A thick set neck, bulging chest. Pale pink legs though not very long. 

Proportionally smaller than the Black-backed, so possibly a female. 

Small but obvious white tips to primaries. Frustratingly no white visible on P10, but browsing pics on the Internet show birds with or without this feature in November birds. Though I never got to an angle where the bird was side on, this image portrays the bird as being very long-winged.

The neck was very 'snake' like being dis-jointed. Mantle faintly darker than nearby argenteus. 

The greater coverts appeared faintly brown but more advanced then I expected. Although not entirely obvious, I did notice dark flecks on the hindneck. The bill and lores appeared long.