Ah, you're right, I mixed up the dates, the establishment of Normandy was after the Danelaw. In this case, the better question: could those Norsemen that went to Normandy be diverted to Wessex instead? If so, I assume full Norse domination of England.
Okay, well several things make it difficult for the establishment of Normandy to be 'moved' to Wessex.
Firstly, the establishment of Normandy started concurrently to the Great Heathen Army creating the Danelaw. Rollo apparently captured Rouen in 876. He subsequently waged campaigns in the surroundings areas till 911 when Charles recognized him as lord of those lands in return for Rollo being baptized and recognizing Charles as his suzerain. So Rollo had effectively been in and cementing his control of modern Normandy, if to various degrees, for decades by the time he was recognized as legitimate. Normandy was an entirely separate front for the vikings. The vikings were spread out, with different groups doing their own things all over the place. Rollo's was Normandy.
Meanwhile Alfred the Great's achievement was preventing the Great Heathen Army from expanding to southern and western England. He also initiated military reforms for defense against the vikings that were comparatively so successful that meant just decades later his children were able to go on the offensive to eventually unite England. It's rather difficult to prevent this except by something drastic like really altering the Great Heathen Army's campaigns. Reinforcements from Scandinavia got caught in a storm. Alfred when first becoming king actually considered fleeing his situation was so dismal. All those Norwegians that fled Harald Fairhair's unification of Normandy could go to England instead of the Western Isles and Iceland like OTL. There's also the go-to of alternate history of just shifting a battle's result from the someone you need gone getting an arrow to the eye. If a rump Wessex survived the initial invasion, you could have a new wave of viking invaders take it around the same timescale as Rollo officially being recognized in Normandy.
However even if you did do something like make Rollo suffer a terrible defeat and then make the Danes successful in England, you haven't quite butterflied some form of Normandy. Normandy was attacked because it was rich, vulnerable, and had excellent rivers as access points for viking ships. So even if you make Rollo unsuccessful, chances are good that a generation later the viking conquests in England would serve as rallying and launching off points for invasions of the northern coast of Francia. So Normandy is likely to come under attack again. However since Francia has immense power inland that could be marshaled if the vikings got too ambitious, they'd never achieve the same level of conquest as the Great Heathen Army. You'd very likely have viking leaders willingly swear fealty to whatever king of West Francia of the time, alongside Carolingian kings who get the idea to recognize viking leaders in turn for them acting as a shield against further viking raids. Rollo was not unique in his status and state of affairs, although his conquest and descendants did prove the most fortuitous in later centuries. So chances are good some degree of Norse-Normandy would come about. Just this time Brittany will likely fall as well since Alan II couldn't retake it without support from King AEThelstan of England, Friesland would be at increased risk of falling under permanent viking influence, and even the County of Flanders would be at risk.
However a warning, a viking conquests in England would probably not be as organized as OTL Normandy. Rollo and his descendants all but assimilated while simply adding a more martial aspect to French culture. Without that assimilation by necessity, you'd likely have Norse England be more Norse in its organization and succession. Meaning, it'd be a mess. OTL Danelaw was disorganized enough that Edward the Elder and his sister were basically able to defeat them piecemeal. So don't expect a Norse England to form a kingdom in the same time frame as OTL Anglo-Saxon England. It would likely follow the centuries of civil war and rebellions like the Scandinavian countries. It'd be more likely to follow Sweden's gradual process to a stable state and kingship, meaning it could stay relatively disunited till middle 12th century.
Summary: It appears you are more concerned about the possibility of a Norse England. Obviously it could happen. In addition to the obvious solution of somehow extending the North Sea Empire, you could also have Harald Hardrada prove successful. A more successful Great Heathen Army and Danelaw is probably third. Long term prospects of England falling into the same sphere of influence as Scandinavia is less certain. The Channel is narrow enough that even during the Dark Ages when international trade hit rock bottom, there was trade between southern England and the continent. Add in France being so rich and arguably the dominant nation for much of the Middle Ages, it's likely there's always going to be French influence. However in regard to Norse replacing Norman in regards to influence, entirely possible.
