Never heard the other versions referred to above: I only know it from the Craig, Morgan and Robson arrangement which is fantastic. It's in one of their books: "When the Snows of Winter Fall" (Graeme Miles song which is in the same book).
Crossing the Bar is in 3-part harmony in this book (key of D)
Obtainable from Reiver Music: www.reivermusic.co.uk or ww.cmr-harmony.org.uk
You can also hear it on Craig, Morgan and Robson Cd "Stranded"