I actually recently finished the timeline for Great Britain (Albaney) in The Raptor of Spain which might be minimally relevant since it features a much more divided Britain. Because my PoD is actually around 750, there are a few different changes that revolve around making Danish and Norse influx into Britain stronger, and the Saxons weaker. This is what I did and maybe it'll give you some ideas.
The most pressing early event is that the battle between Wessex and Mercia that in OTL was known as Ellandun and won by Wessex, is instead won by Merica. This kingdom keeps its dominance, weakens Wessex, but is in a worse position to resist the Viking attacks. Stronger more unified polities in the Carolingian Empire, Hispania and Ireland result in Britain becoming a more attractive target further putting a hurt on the Saxons.
More vikings mean more are willing to settle down and become mercenaries for the Saxon kings who fight each other. They settle among the Angles who are more culturally aligned with them than the Saxons furthering their demographic power slightly. Thus settlement begins about 20-30 years earlier relative to OTL.
The end state is that through chance and greater infighting, "England" consists of 4 major kingdoms, Saxony (Wessex), Mercia, Jorvik (Northumbria), Anglia and one minor kingdom that survives because it centers on London. All but Saxony are either Anglo-Dane or Saxon-Dane. Periodically, a strongman or dynastic union enables someone to dominate the south as "High King of Albaney." However the other states generally band together in rebellion after the death of the strongman so unification has not yet stuck. For a very brief time around 902, the country was united under a Danish king. This king conducted what I called the "Harrowing of the South." Basically what Guillaume the Bastard did to Northumbria in OTL, the Danish king did to Wessex but this control lasted barley a decade.
Currently there is a High Kingdom (fourth one I think), this time centered on Jorvik, but its control is very loose, settling for tribute and lip service rather than actual control. So maybe they'll be united yet... or maybe not. Regardless the country is far more war torn than OTL and somewhat more divided by language and custom. Current year: 1146. Also since in RoS the vikings invaded and conquered Aquitaine instead of Normandy, you're not going to have a 1066 scenario with a continental invasion so the island is much more firmly involved with the Scandinavian countries than with the continent.