Hi Magnus,
You could be right, the problem with small images! I noted the warmth to the UP's of the first, perhaps reflective? As I can't enlarge, I cannot see the white inner vane, I'll take your word for it. Structurally, it would be at the 'thinner' end for Brown, so I'd happily swing toward RBF providing I could see a bigger image..
With the Prinia, same problem for me, a lack of enlargement, interestingly, my other choice would have been Plain, but without seeing clearly, I plumped for, perhaps the wrong one!