Yellow-legged gull?

Saw this on Tuesday afternoon, piling in with the red kites at the feeding station near Aberystwyth.  Is it a yellow-legged gull?  It doesn't look quite dark enough to be a lesser black-backed to me.

Any help much appreciated.

Our herring gulls are red listed birds.  Think about that the next time you hear some flaming idiot calling for a cull of them.