probable yellow legged gull on tyne

Had a probable ylg on the tyne at stella today, ive got to look into it a bit more before i call it but its looking good, rba and gull research have both being sent the photos, ive had an email back from rba and it does look good for ylg but they have to look into it further to make sure its not a hybrid? Lesser black backed x herring. Here is a couple of photos, it would be a gateshead lifer for me if its eventually called as a yellow legged gull? Fingers crossed ;)