Hi Pudweena, this is a Mediterranean Gull, notice the black mask, lack of black on the wing tips and thicker bill.
I remember them by thinking about a "mask of zorro" plus watch their behaviour as they they have a habit of staring at their feet in a gormless way !! Tends to mark them out in a group !!
A bird doesn't sing because it has answers. It sings because it has a song.
Thanks for the info. and photo Paul, thought you are supposed to be on holiday! So confusing all the different plumage of Gulls, like Ducks but I see the comparison.
I like your description cj, will check in future if they look like they are staring at their feet, handy little tip and easier to remember too!