These are really beautiful gulls, with the most stern looks due to their deeply seated yellow eyes circled by a red eye ring. The individual at the top was particularly stunning, its red spot was really bright and extended extending to the top side of the bill, like some badly applied lipstick.
Here, Lesser Black-backed gulls are summer birds, from March to August, and presumably breed atop buildings locally.
Four of the Lesser black-backed gulls
Lesser Black back gull on the water
A pair by the water. Note the darkish ring on the top of the bill, indicating these have recently adquired their adult plumage (about 5 yr old). Note also the different tone of the yellow legs.