I had to read that twice, Lord B!
Strictly from the point of view of British national interests it would be better if she won in that the French are really in need of the kind of tough reforms that Sarky says he'll do - without them, they'll continue to disintegrate as a country - and she won't be able to put such reforms in place. And what's bad for France is ipso facto usually good for England, as De Gaulle said (though he put it the other way round, of course!)
That said, I suppose it would be a shame to see a once great country go down the pan.