"They're still using "England" in an anachronistic usage, to some extent ... Ethelraed's kingdom wasn't exactly a united polity, as was demonstrated in the runup to 1066."
In fact, arguably, the 9th-century viking immigration/invasion of what became the danelaw, and the subsequent expulsion of danelaw rule from those areas by alfred and his descendents, in fact contributed greatly to earlier consolidation of the nominal rule of the major kingdoms that would have otherwise been the case.
Excellent point.