I finally gave in to the draw of the Lesser Scaup this morning; the bird was (for the most part) sleeping amongst the Tufteds at the afterthought of a nature reserve on the edge of the former Taff/Ely Estuary SSSI. Didn't manage to see any Greater/normal/bulk standard Scaup or the Slavonian Grebe, but one shouldn't get greedy, and I did get to see a Mute Swan fly headlong into a buddleia so it wasn't all bad.
Dropped in on Lamby Way on the way back, got more views of the 2nd-winter Ring-billed Gull and a pristine adult Med Gull dropped in making all the Black-heads look just a little bit grubby. The 1st-winter Ring-bill and Bittern avoided detection but I did get to meet a certain world-renowned birding dog.
Peterstone Gout was worse than useless, in fact it was worse than my garden which turned up Blackcap.