FWIW, mushroom rings are real, at least in the UK. They seemed to be affected by EMF, because I wandered past one centered directly centered under street power lines, I have no idea whether that's where a ley-line intersect it or not. I don't think they were psychedelic mushrooms though, but it was pretty cool seeing them growing in a large circle about 3-4m in diameter.

The main point of the article is that they're psychedelic, but don't contain psilocybin as the active molecule.

In earlier centuries it doesn't seem unreasonable to allow the possibility of the mushroom ingester to describe their experience as visiting the fae realm, whether in the UK or otherwise - as an accidental occurence I don't know how else people from the past would be able to explain what they perceived to others?