AbsintheRed
Deity
Imho:
All those areas were Viking controlled, but primarily settled Danish Vikings - hence the term Danelaw. They belong in the Danish UHV (and indeed are there), but shouldn't be in the Norwegian UHV, as the Norwegians primarily invaded and settled western Scotland (i.e. the Kingdom of the Isles), Ireland, and the Northern Isles. The Norwegian UHV should focus on those, and indeed they do, except for the awkward inclusion of Mercia.
Yeah, Mercia was added there by mistake
So the UHVs will be: TheIsles, Ireland, Scotland, Normandy, Iceland for Norway
Mercia, London, EastAnglia, Northumbria for Denmark
EDIT: Maybe we can add Northumbria to Norway too, even if that's not completely historical
The province stability level is a different question
I don't mind if some of these provinces are better than unstable for the other civ as well
It's mainly for the human player after all, we can make the Viking conquest somewhat more fun