Very odd, but worth sticking with. Streams of consciousness, or more accurately subconsciousness, pervade this story. And a very weird ending. And it is set in and around Cadair Idris. And the telephone box is there - so you can dial Surinam if you want to.
So here I am in a big circular underground chamber. The whole place is flooded with sunlight. There's a large dome above, maybe fifty feet up, and high above that I can see a huge ellipse, like a crystal lake, hovering in improbable space. Directly under the dome there are several tiers of precarious-looking wrought iron galleries, planted up like the hot house at Kew.