Bonaparte's Gull at Barking Bay

I was at Two Tree Island Essex, when Dom texted me to say that Rich Bonser had found a 1s Bonaparte's Gull at Crossness. So myself and Martin Redfern jumped in the car to try and connect with this London Mega. Luckily Paulboy had refound it, after it flew west. I must admit its not a easy bird to pick out at a distance well done Rich. Thanks to everyone for the info. Here are some record shots below.