in the UK, areas associated with Paganism and Druidic beliefs have high growth rates of liberty cap mushrooms. Were psychodelics a prominent feature in these religions and did they ever struggle to expand into areas where the mushroom is less prominent?

While there will be always more to be said on the topic, both /u/wotan_weevil and /u/sunagainstgold unfortunately agreed before in: Were magic mushrooms or other hallucinogens used in medieval Europe? that the popular conception of alleged wider use of kind of magic mushrooms in medieval popular beliefs were largely based on the modern invention.

[Added]: The following previous answers are also negative on the possible wide use of mushrooms as hallucinogens in medieval Europe:

Is there truth to the claim that Vikings took Psilocybin mushrooms before going into battle/pillaging etc? by /u/textandtrowel
Were psilocybin mushrooms ever traded in Post-Rome Europe, brought there by merchants, or in any way accessible to average folks? Were early colonists ever exposed to them in any way? by /u/issiwo_1