Are they both just Herring Gulls or is one a Yellow-Legged Gull?
No interactions present.
I would say these are both lesser black-backs, judging by their long wings and very dark tertials. Yellow-legged are much lighter on the head and neck in juvenile plumage with very heavy bills. Their tertials are dark but with broad white margins. The best feature is in flight though when they show a bright white tail with a broad black bar. All three species are pretty tricky at this age but get easier as they get older!
Lat/Lng: 51.3208, -2.6167
OS grid ref: ST571581