"Go to the left, and death awaits you -- go to the right, and death awaits you" -- per atlas, west of Mitcheldean Road station there's supposedly a triangle, leading south onto the Mitcheldean Road & Forest of Dean Jun. Ry. (never actually operational between M.R. and Drybrook Halt) -- on general principle that one will be wrong whatever one does, I'll avoid Mitcheldean Road and make the next -- Drybrook Halt
While I was waffling as above, Whistler40145 decisively went for Mitcheldean Road. We're off south thereof, "whatever" -- learned scholars, please weigh in.