In this timeline the Norman invasion occurs on schedule and although the Normans defeat the Anglo-Saxons they suffer much higher casualties and are unable to fight off the Norwegian invasion. The end result is a Norwegian kingdom reminiscent of Cnut the Great's North Sea Empire.
Norwegian Conquest of England
In early August of 1066 a Norman fleet carrying ten thousand men led by Duke William sailed for England despite unfavorable conditions and landed on August 21st. They were met by an Anglo-Saxon army of twelve thousand men under King Harold Godwinson just ten miles north of Pevensey. The Norman army defeated the larger Anglo-Saxon army due to better tactics and equipment but suffered almost four thousand casualties. In September William's march towards London was interrupted by news of a Norwegian invasion of the north led by another contender for the crown, Norwegian King Harald Hardrada. Rather than await reinforcements from Normandy Duke William marched north drive off this army despite not knowing it's size.
The two armies met on October 10th, 1066 in the Battle of Rushcliffe, the Norman army of six thousand was outnumbered by the Norwegian army of ten thousand. In an almost one sided battle the Norwegians killed almost three thousand Normans, Duke William among them. Only two thousand Norwegians fell but Harald's English ally Tostig Godwinson, Harold Godwinson's brother was killed. With both of his rivals dead King Harald's claim to the English crown was the only legitimate claim remaining and was crowned King of England on November 11th, 1066.