I'm hopeless at identifying gulls but I think this is a Herring Gull because of the three large white spots on the black tail.
No interactions present.
This looks all wrong for Herring Gull, and in comparison to the BHG size is right for Common. It also appears to have the dark eye of CG, not the yellow eye of HG.
recording wildlife with The Recorder's Year on www.hbrg.org.uk/TRY.html.
Looking at the eye of the Common Gull in my book I can see what you mean. It does look a neater bird. Now I shall be alert for eye colour, size and 'conduct'.
Certificate in Contemporary Science (Open)
There are some objective characters to separate these two gulls - bill and leg colour being easiest. But they are very different in jizz. As Apus mentioned, HG has a fierce look, with a wedge-shaped head and pale eye, while CG has a rounder, kinder face with a dark eye. Look at the ones you have and you will soon recognise them without having to see the legs or bill, just from their jizz.
Lat/Lng: 51.41932, -0.95828
OS grid ref: SU725694