I have tasted several different offerings from commercial brewers as well as homebrewers......... and they all taste totally different. This gives me the impression that no one really has a very good grasp on the keys to the style. I'll bet the offerings of today taste NOTHING like the historical versions. But of course, I don't have a time machine so we'll never know what it truly tasted like.
I've brewed my own version, many years ago when sour mashing was the thing (now some people insist that sour mashing is totally wrong -- whatever). Even so, my homebrew did NOT taste sour in any way shape or form. The one I made tasted like an English brown ale, but had used a high proportion of corn if memory serves. The English wouldn't have a problem using adjuncts either. So based on that, I think it's supposed to taste like an English ale, kind of, maybe. But I'll freely admit, I'm probably wrong. I'll also freely point out that any version you can find out there is probably wrong too. The BJCP guidelines are guidelines, but I really don't know if they're right either, but they probably have the best info we can get. The sour mashing thing is what irks me. I think it makes sense, and should make for a more unique beer. BJCP disagrees. I disagree with their disagreement. But whatever.
Wish I had a time machine.