I favor a prostelyzation effort from Ireland to North Umbria and/or Mercia. Maybe an order with open monasticism that prize martial arts, and parochial abbatial charity; priests that prize plainness/simplicity, and perhaps even with a Greek Orthodoxy affiliation. And who doesn't love babies - so no priestly celibacy. The Angle king sees is saving save on money that would go off to Rome, his people are well cared for in childhood and old age, and the system of fort monasteries and protoburhs keep enemies in check.
In the face of the coming Viking Raids the Angle kingdom begins to take other realms in the Heptarchy. They realize the value of a strong navy to help deter the raids, and go on to unite the rest of England, Ireland, and Scotland. Looked at as brothers in Christ, the Anglicans are welcomed as liberators. Holding true to democratic principles (and IMO republican tendencies) the Witan is maintained as a representative parliament for all the shires in the united realm. The fyrd, combined with the fighting celtic monks encouraged a system of widespread weapon ownership and military training even among the poor folk - this worked to keep the rich folk and bureaucrats honest.
Scandinavians are allowed to immigrate in small and scattered numbers upon baptism and oaths, and over time their contributions even work to reform the syntax and vocabulary of the English language. Wales eventually is incorporated. Anglocelt ships and missionaries routinely reach Iceland and the Baltic Sea, with routine trade to Italy and Byzantium keeping money and goods coming into Britannia.