Which gull?

I initially thought that this was a black-headed gull, but the legs and beak are the wrong colour:

I then wondered if it was a common gull but I don't think they have that black eye:

It's certainly a lovely looking bird and I'd love to know which gull it is!  As always, all help most gratefully received.

I should add that I got these today at RSPB Snettisham.

Our herring gulls are red listed birds.  Think about that the next time you hear some flaming idiot calling for a cull of them.