Juvenile Yellow-legged Gull?

The juvenile Gull season is now upon us and typically 1st out of the traps are Yellow-legged Gulls so when I picked up these juvenile bird amongst our band of mixed aged, non-breeding loafing large Gulls which frequent the football fields and Alexanadra Lake throughout the summer, straight away I was thinking Yellow-legged Gull - but it wasn't the most obvious of individuals and it could actually be a juvenile Lesser black-backed Gull!

Thought and comments welcome?

Also of note was the discovery of a juvenile/female type Common Redstart in the brooms, my 1st ever record for July and more proof if needed that Autumn is just around the corner...bring it on!