It has been a while since I looked at this (more than a decade since I wrote my book on "King Orfeo"/"Sir Orfeo"), but the consensus seems to be that all the choruses are so zersungen that they are beyond recovery.

The Collinson text is in Bronson IV, pp. 455-456.

If you want to contact me privately, I'll give you the relevant chapter of Romancing the Ballad, but I'm not going to spread my own copyrighted work all over Mudcat, even if I don't get paid royalties on it. :-)