Finally managed a day in Slimbridge - been looking at the weather forcast for weeks. On the centre's website I saw that there was a bird I had never seen before - the lesser scaup - so this was my first target. On the website the location was supposed to be the Rushy but we found this bird in front of the Martin Smith Hide:
Both taken with 500mm lens and 1.4 converter, ISO1000 f8 @ 1/2500sec.
The other information I read on the website was that on the South Lake there was a pair of Great Crested Grebe nestbuilding. We watched them for most of the day and managed this shot of them head bobbing (but not 'dancing'):