I've never heard the chorus, which you are referring to as the first two phrases, used for Bring Us In Good Ale. Many years ago, though, I recorded the Christmas carol version, The Salutation of the Angel. It's really an Annunciation song more than a Christmas song. You can hear a little piece of it at CD Baby; unfortunately the clip doesn't include any of the chorus in question. When we recorded it we had found a version in Chappell's Old English Popular Music that goes from 3/4 time to 4/4 in the sixth measure of the chorus.

My favorite thing about Salutation of the Angel is how Mary tells the angel that she's a virgin after being told she's going to give birth: "By what manner should I child bear, the which, ever a maid, have lived chaste all my life past and never man assayed?"