Togo, the only appropriate dance for the England rugby team in response to the Haka would surely be a Morris dance. That'd put the fear of God in 'em!
Naomi, the English are obviously perfectly welcome to choose a 'hybrid' anthem...ie one clearly involving the Scots, Welsh and Northern Irish as well as themselves. However, I should have thought something more nation-specific would be required for a proud people.
I hate the blessed thing, but at least Flower of Scotland is clearly Scottish and there is only one land involved in Land of my Fathers. Irish rugby has a form of joint anthem, but both ‘elements’ have taken to singing it with some enthusiasm; they are all, after all, Irish.