Aston Sandford, Nr. Haddenham
Thanks to forum member Tinker, the entrance to Lower Moat Manor was found to be in the small hamlet of Aston Sandford near Haddenham.
The road leading up to Aston Sandford was used for the junction shot in the episode. Thank you to Carl Jones for identifying this.
In the final scene of the episode, where Rayburn, as a tramp, is walking through the fog, you can see Aston Sandford church in the background. Thank you to Tinker for finding this location.