In the afternoon went to Knowl Hill and managed to walk through the snow to a point where I could see the landfill site. I scanned the feeding birds and eventually managed to pin-down the 1st winter Glaucous Gull sitting on a small hummock. I initially picked it up on its distinctive bill with obvious black tip, but later it stood up and then was able to appreciate the large size, creamy colour and lack of black in the wing.
On the way back to the car I saw a couple of female Siskins in the larches.
I then went over to White Swan Lake (Dinton Pastures) where I stood in the freezing cold scanning for the Bittern. Then a regular guy turned up and told me that the birds (there were supposedly two Bitterns) would be feeding elsewhere as the lakes were frozen and should fly into roost. Based on this recommendation I then went and stood right next to the reed bed and a not long after a Bittern flew into roost right in front of me and sort of crash landed in the reed bed to the right of the large bramble as you look out over the lake.