Can anyone tell me what type of gull this is? See today, Jersey

Juv/ 1st Winter Herring Gull - most of the Gulls that you will find around St. Helier, St Aubin, Gorey and Rozel tend to be Herring Gulls. Doesn't mean that you won't see Lesser and Greater Black Backs but they don't interact with people quite as much

Young Gulls are really tricky so well done for having a go and over the 3 to 4 years they take to mature offer different and similar colour variations. We mainly have Herring, Lesser Black Back, Greater Black Back and Black Headed Mediterranean Gulls, rarely Common and Yellow Leg, Icelandic or Glaucous but anything can crop up if we have had interesting weather.
Working list of CI birds. Gulls Start on page 23
cdn.website-editor.net/.../Working%20list%20of%20CI%20birds%20to%20Dec%202021.pdf