After numerous attempts I finally saw the Freckled Ducks at Lake Monger this evening. They have been hanging around for a few weeks now and steadily increasing in number (five were present). It turns out I had confused east and west and had been checking the wrong area of the lake.
As an added bonus John Graff’s expert Little Grassbird mimicry yielded good views of a specimen just before dusk. These two birds are numbers 267 and 268 on my life-list.