No way. The "worn out from beating the Normans" effect is exaggerated in popular history anyway, as the Normans were just a raiding party with a megalomaniac leader (John the Bastard? Or am I confusing him with someone else?). It's just impossible for the Angles to beat the Danes, at least with Harald the Conqueror leading them. But maybe if Harald gets butterflied away earlier, a more timid Danish leader doesn't even press his claim to the Angle throne, and we could get an Angle-land that lasts a few more centuries (to the present day even? Or is that ASB?)