The first letter of the newspaper is clearly an upper-case eth, not a d.. Weird mistake for a researcher to make!

Upper-case eth? That would be a Ð.

I assumed it was a cyrillic glyph, but that doesn't seem to be right either; the closest I could find was ъ, which loops the wrong way. It would appear to just be a glyph the newspaper people made up, like the I-like vowel that follows it, or the one representing the ng sound, or the filliped O in "Anglo".

Why pick on the researcher? She couldn't type the invented d-like glyph, so she used an actual D. She couldn't type the invented ng-glyph either, and used an n, but you're not complaining about that.

Because the name of the newspaper is 'Thi Anglo Sacson'. The reversed N is another decorative glyph.

I suspect rather that the reversed N is a take on the letter ŋ (https://en.wikipedia.org/wiki/Eng_%28letter%29), or "eng", since that's the sound that the 'n' in 'Anglo' makes anyway (when followed by a 'g').

None of the glyphs are decorative (as is made clear in the article, if you read it). The point is to have the writing reflect pronunciation.