Though there were swimmers already in the water when I got there, and swimmers in the water when I left, during my thirty minute swim I had the privilege of being the only human swimmer.
I shared the lake with amongst others, Mute Swans, Mallards, Cormorants, Great Crested Grebes, Little Grebes, Coots, Moorhens, and an assortment of gulls.
Many of them don't seem to recognise swimmers as a human danger, and they will let you get a lot closer than normal, giving some very good views.