Having dipped this bird a few days earlier with Kris Wade I gave myself a bit more time today to wait for the bird to make appearance.
This time I waited around an hour before the bird appeared on the grass bank beside the lake, standing out like a bright white beacon amongst the slightly darker juvenile herring gulls.
Typically they the head is proportionately quite small and pear-shaped, showing the characteristic sloping forehead, which is further enhanced by the long and slim bill.