There seems to be an issue with the Xbox Achievements (played on Xbox One X). Arrived in England, but so far no Achievement has popped. There should have been at least two, for completing the prologue and for leaving Norway.
Have you confirmed with Xbox Support that the achievements should have been unlockable? It sounds like you may have been playing prior to launch day (today!) so this may have contributed to your issues with unlocking achievements. It's worth checking with them.
If you do continue to have issues with these achievements, please post again in our new forums for Assassin's Creed Valhalla, and be sure to tag your platform and issue type. Please state the specific achievements you are having issues with, as well as their unlock conditions.