I went in search of Yellow-legged Gulls and left instead with a photo of the purple-pencilled flowers of Gipsywort, which I found growing alongside the boardwalk. Finally nailed a Willow Warbler with confidence, so progress on my birdsong and call journey. Oh and there was a good showing of by a Marsh Harrier too.
The Urban Naturalist 
Very interesting Amanda, I have never knowingly seen the plant but it reminds me of some aspects of the dead nettles