Just watched the episode with Lud's Church. It reminds me of a place in North Fife. The area is reached by walking down through a wood and climbing down some roughly hewn steps into a 'dell'. At the top of the steps is a pool which is about 4' deep that is known locally as the Druid's Pool. Adjacent to the steps is a small cliff where Celtic carvings have been cut, and where candles could be and have been placed. Throughout the 'dell', (which has a river running through it), over the years people have hung ribbons, beads etc on tree branches. The whole area feels really peaceful.
I believe that it has been and might still be, an area of Pagan worship, although there is a church close by (often the case).