Why was Bendigeidfran's head buried facing France and not Ireland?

Question

In the second branch of the Mabinogion, the forces of the Isle of the Mighty (Britain) defeat the Irish, though only seven survive. The dying Welsh king, Bendigeidfran, orders his men to cut off his head, bring it back to London (after a stop along the way) and bury it, facing France, where it will protect the island.

'Take the head' said he 'and bring it to the White Hill in London, and bury it with its face towards France. And you will be on the road a long time. In Harlech you will be seven years in feasting, the birds of Rhiannon singing to you. The head will be as good company to you as it was at its best when it was ever on me. And you will be at Gwales in Penfro for eighty years. Until you open the door facing Aber Henvelen on the side facing Cornwall, you will be able to abide there, along with the head with you uncorrupted. But when you open that door, you will not be able to remain there. You will make for London and bury the head. Cross over to the other side.'

Why would the head face towards France, and not Ireland, given that Britain and Ireland had just fought an extremely violent (albeit shortlived) battle? Would the Irish, though extremely weakened, if not virtually destroyed (and therefore not a threat), still be disliked far more than the French?

Answer 1

The head was placed facing France to protect Britain from Saxon invasion. Ireland, was no longer a concern (emphasis mine):

'Shame on my beard,' said he 'if I don't open the door and find out whether it is true what is said about it. [So] he opened the door, and looked out to Cornwall and over Aber Henvelen. And when he looked, suddenly everything they had ever lost - loved ones and companions, and all the bad things that had ever happened to them; and most of all the loss of their king - became as clear as if it had been rushing in towards them. And from that moment, they were not able to rest unless they were making for London with the head. However long they were on the road, they came to London, and they buried the head in The White Hill.

And that was one of the Three Fortunate concealments when it was buried, and one of the Three Unfortunate Disclosures when it was unearthed: since no affliction would ever came to this Island from across the sea, as long as the head was in that concealment. That is what this tradition says. Their adventure 'The men who set out to Ireland', is [the name of] that [tale].

In Ireland, there was no person left alive, except five pregnant women in a cave in the wilderness of Ireland. And to those five women, after the same amount of time, were born five sons. They raised those five boys until they were fully-grown youths, and they thought about women and desired to take them. And then, each sleeps willy-nilly with the mother of his companion, and rules the country and inhabits it, and divides it between the five of them. And because of that division, the 'Five Parts of Ireland' are still so called. And they searched the country, wherever there had been fighting - and found gold and silver, until they became wealthy.

_{Source: The Mabinogi of Branwen}