Another good interdimensional portal: the Tolmen Stone on Dartmoor, above the North Teign river on Dartmoor. Said to cure rickets, rheumatic fever & various other ailments when you pass through it from above. Also quite a useful location if you are shooting the cover for your debut psych-folk album.
Tom CoxThe UK countryside is full of interdimensional portals. You just have to know where to look. I've decided to make a thread here of some of the best ones I've found on walks. 1. JRR Tolkien's Psychedelic Lime Kiln.