If you use Logria (which you mentioned in a previous post) not Logres, then Logrian is the obvious demonym.another thought occurred to me: what would be the best demonym to use...?
Well they tended to borrow any Brythonic words via Latin so we can assume Middle Welsh L(l)oegyr comes from Roman-British Loegirum, Loegria, or Loegres.also a good point--i hadn't considered that the Anglo-Saxons would have their own version of "Logres"