In no particular order:
1.Banks Of The Sweet Primeroses
2.Claudy Banks
3.John Barleycorn
4.Seven Yellow Gypsies
5.Little Musgrave and Lady Barnard (Or Matty Groves, etc, whichever)
6.The Trees Do Grow High
7.Brigg Fair
8.Here We Come A-Wassailing
9.William Taylor
10.The Happy Man

My two cents: representative to me has to include a sustainability. If every major English folk musician has performed, or wanted to perform these songs at some point, there is a reason. Yes, the tradition goes deep, but there is a reason these songs are performed again and again. Mind you, there are sometimes better, darker, creepier, funnier, or make you lust for a pint songs than these songs, but they haven't stood the test of time (or been transcribed in books more!). To me as well, the songs have to "smell" English. Take tunes for example. When I listen to the tunes that someone like, Brass Monkey arranged, I am instantly transported to England, same as when I hear bluegrass I'm in Kentucky, or an Irish tune, in a pub in my dear Donegal! Banks Of The Sweet Primeroses, or The Happy Man, etc, just transport me, and for that reason, that is why they are here. Cheers,