all are Lesser Black backed Gull imo.
Please note the right dark shade of upperparts (lacking bluish tinge), the right yellow legs, small white mirrors and gently rounded head, lacking the powerful head-bill profile of many YLG ). Narrow red orbital ring also fits LBBG.
Regarding head pattern:
Typical YLG lacking the fierce, brute head-bill-jizz of Great BBG. I often say, wouldnt you like your parents to be YLG? They have a strong and confident, still gentle head-bill profile that gives you a feeling of warmth, security and safety. Not a brute Great BBG (I am no biologist, I am sure, GBBG are wonderful parents, too)
In contrast, your bird has rounded head, good for an ID-book LBBG (and Herring Gull)