In a footnote Bowers quotes from an email he received from Sisam's daughter (herself a scholar of note) that includes a judgment of Tolkien over the Tolkien/Gordon edition of Sir Gawain to the effect that EVG did all the work:
"I gathered from my father that that edition
was almost entirely the work of his co-editor,
E. V. Gordon, as Tolkien was so dilatory and
didn't produce his share" (Bowers 54–55).
I suspect here Celia Sisam is conflating Gawain with Pearl, another project which Tolkien began in collaboration (again with E. V. Gordon) yet failed to finish, turning over all his material to Gordon's widow who drew on it to complete the edition herself. The Clarendon Pearl strongly resembles The Clarendon Chaucer in inception, abandonment, and Tolkien's willingness to turn over all his material to another editor. It differs primarily that in this case a new editor stepped up to finish the work.
That Tolkien and EVG were equal partners in their creation of the Gawain edition is certainly the impression that emerges from Douglas A. Anderson's "An Industrious Little Devil" (in TOLKIEN THE MEDIEVALIST, ed Jane Chance, 2003), which I take to be the definitive piece on their relationship. It also seems unlikely that if Tolkien were to have performed so badly on SGGK that the Press wd promptly sign him up for another similar project. Still, it comes as a striking example of the anti-Tolkien sentiment that lingered for so long among some of his fellow academic scholars
--current audiobook; Aaronovich on conspiracy theories;
--current reading: Lehner on Pyramids, Christopher Tolkien's RETURN OF THE SHADOW (rereading)