Regarding the origins of the song and the various lyrics posted up here i think it is fair to say that the song itself is evolving as different singers adapt or substitute different words/verses etc. Surely this is what folk music should do - evolve to become relevant to the singer and the time in which they are singing the song? That, in my opinion, is what keeps folk music alive, instead of it remaining archaic and irrelevant to more modern times (probably upsetting all the trad purists here!!). Songs like Scarborough Fair which have a thread such as love running through will alway be sung as long as people find resonance in the song itself, hence why it's adapted over time or when different people sing it. I myself do a version that is sung from the womans point of view however still keeps the main words intact but also brings in male voice harmony in a nod to the original theme. It's a lovely song to sing or hear and i worry that it's in danger of becoming over done in the Simon & Garfunkel style because too few people want to take it in a fresh direction.
That's my two pennies worth of rant!!!