I like the book because it involves religion and time travel… something of recurring themes in Holdstock. Maybe he knew it. But ya probably not related… i still kinda want to read it thoughThis has been brought up previously and very likely is just a coincidence.
Post in thread 'The Quest To Find Raxxla'
https://forums.frontier.co.uk/threads/the-quest-to-find-raxxla.168253/post-6357171
Written by:
ANDERSON, KATHLEEN [AGNES CICELY] (21 Jan 1888 – 14 Apr 1972)
(aka Sister Mary Catherine)
1930s – 1940s
Biographer and author of four novels, including Brother Petroc's Return (1937), The Dark Wheel (1939), The Spark in the Reeds (1941), and The Flight and the Song: A Tale of Old Devon (1946), the last co-written with her sister, novelist Lilian M. ANDERSON. She also wrote four biographies—Henry Suso, Saint and Poet(1947), Steward of Souls: A Portrait of Mother Margaret Hallahan (1952), Margaret, Princess of Hungary (1954), and The Chronicles of Thomas Frith(1957).
In 2015 The ‘Preserving Christian Publications Inc’ gives a very short synopsis: “A story in which a modern atheist is transported to the 16th century”.
On a separate note, and likely not related to this publication, the 16th century proposed the heliocentric universe and Tycho Brahe refuted the theory of ‘celestial spheres’ through observational measurement of the 1572 super nova…
The image you identified on the front cover is called a Chi-Rho and is most likely part of that books publisher’s monogram - it being a catholic symbol, and a Christian based work; although it does have roots in pre-Christian symbolism; such as sun wheels and runes, but doesn’t everything.

oh also i think you were more right with the sun wheel description … Id call it a solar cross. Not quite a chi rho as it doesnt make the letters.