As to what us lot are singing in pubs today, well it's a right mixed bag. But as I said, I'm guessing your audience might want something identifiably English. As you're there just to entertain, I'd probably go down that route. There is quite a lot of traditional English songs at one of the pub sessions I go to though.

Otherwise you could try songs by English folk artists *about* England. Billy Bragg comes to mind as a high profile singer songwriter whose material might work for you.

http://www.youtube.com/watch?v=3jphA05ka6E