Well, it seems logical the names are different in the case of Asterix. It makes much more sense than changing the location of a battle.
(Agincourt wasn't probably in France in those days)
Erh, UE, do you know all these people that are held captive in Albion? I don't know one or two of these. But at any rate, I, in the name of the French Republic, must regretfully decline your proposition, as we strongly believe your two current hostages love England. *Thinks* And while they are busy toying with their hostages, we will try to invade England once again, as it is the first step of my plan.
Erh, I seem to recall we were speaking of rugby, weren't we? Hopefully, England will play against France, the former being victorious. (How to make friends with about 60 million people in a few seconds)