To split Britain in two like that, have the 1066 Norwegian invasion of England work by having Harald Hadrada beat Harold Godwinson in the Battle of Stamford Bridge
Then the 1066 Norman invasion of England three months later is also successful
The Norwegians and the Normans split the island between them: the Norwegians base their capital in York, the Normans base their capital in London
Would this also work with Jutland (Angeln) being part of England? I mean, would that be a possible result of this POD too? If so, would you know how?
EDIT - Oh, and a note is that England on the map actually isn't, like, Danish, but Jutland is English. I know, kinda obvious, but just pointing that out to be sure you're aware of that.