When first seen it was in heavy shadow, and being an irregular taxa to my site, I generally default to C.cabaret...unless other features are observed (size/general paleness etc.).
However, I was struck by the amount of “apparent” white shown in the raised wing image, although I have seen cabaret with small areas of white in the rump before, this seemed a little excessive, what a buggersome group they are!...will keep my eyes peeled.
Cheers