I spied this streaky brown bird on the ground at the RSPB's reserve at Dungeness, but I can't quite convince myself of what it is. Front runner is a female or juvenile Linnet (not the red-marked male) but it could be a Twite, or maybe something else entirely? I've endlessly studied pictures, videos and descriptions of the two prime contenders and it doesn't quite look like either: for instance having the wrong colour legs, lacking white wing markings, wrong colour bill, more accentuated facial patterns etc.

Will somebody who's familiar with the birds of the region please put me out of my misery?

Update: some Twitterers have suggested that it's a female Reed bunting, and I think they're absolutely right. Quite why I didn't think of that I have no idea, seeing as we saw plenty of the more obvious males. Here's an example of the male, and though it's from a different angle you can see it's very similar apart from the black and white head. This one also appears to be ringed.