Maybe it is the the reviewer below who has wild theories. The fact is that Lewis Spence was, and still is, recognised as an authority on faery lore and Druidic matters, for which reason he was linked with the British Druids during the time that Robert MacGregor-Reid served as the Arch Druid. This is recorded in "The Book of Druidry" by Ross Nichols, the Arch Druid who succeeded MacGregor-Reid. The present Arch Druid of that order (OBOD) is Philip Carr-Gomm. Lewis Spence was an extraordinary researcher and scholar. He still enjoys the respect of the Druids. His books are worth reading.
Wild theories. That is all I have to say. Not worth your time.