The chap who runs the In Flanders Fields museum is a bit of a folkie, from what I understand, and a friend of Lester Simpson's. I think this is how Coope Boyes and Simpson came to record and perform their Passchendale Suite over there. The museum also uses a very charming version of Robb Johnson's Harry Took Me To Ypres which you can hear on their website.

In response to the original question, June Tabor's version is so moving, and so haunting, it gets my vote.