I read this book as a child and it stuck with me as an anonymous shaper of the cosmology of my imagination, in the way certain books do if you read them at a formative time. Decades later I realised you can track these books down nowadays.
I was pleased to find it was worth the remembrance - properly alien faeries and much more folk horror than I thought child me had a taste for. I am truly astonished this was written by a 16 year old, it does not read like that at all.
that a later book of hers, the Ghost Drum, had also had a big imprint on me ( I never noticed author names at the time as I had no access to library or book store, I just read voraciously whatever paperbacks my father brought back from charity shop).
I wish the author was better known. Maybe my child will carry this one a bit further on.