In reply to:

One link was about Dion Fortune's "The Goat-Foot God", which had a character called Mr. Jelkes, the owner of an occult bookshop who was trying to set up a centre for occult studies in an abandoned monastery.

Wouldn't that be the oddest thing, Bingley, if Williams named the ethereal, artistic Miss Jelkes after a character associated with the occult--and writer, too!? The women in the play are different facets of the female--the female torn into three guises. But Shannon is clearly drawn to the spiritual Miss Jelkes--and she completely lacks the sexual spart that is part of the conjunction of Shannon's fall. He is such an overtly sexual--yet at the same time sexually repressed character. And Miss Jelkes is of the Spirit--the real Spirit--the Spirit that the Church has lost in Shannon's view.

So, I wonder about your Jelkes theory. There may be a bit of truth in it if it could be shown that Williams was interested in Dion Fortune.

Of course, Miss Jelkes jilts Shannon...and there's that 'j' and 'l' connection, too.