Mick, thanks very much for that reference. I had not seen it and look forward to reading it. By the way, after getting hold of the Heylin book, I checked and the online article does contain the whole book, with the exception of the notes and an appendix containing copies of all of the versions having the "heaven/hell" verses, and a pretty good bibliography. There is also a page of followup on Heylin's quest for the source of Dylan's version, which I will discuss a bit later. There is also an in depth review of the Heylin book by a Christopher Rollason from 2004 here (you have to scroll down to find it):

http://nicolamenicacci.com/bdcc/bookreviews.pdf