Lleolwyd Cerddwyr Coll - Two walkers left Elan Valley visitor centre at about 16:00 and walked up the hill on a path that disappeared. It then became dark so they called for help. We made contact with the walkers, checked they were ok and made a plan for them to self-rescue. I sent them a photo of their position and we repeated this several times with them using 'phone find' to monitor their position . They were met on the main path by an Mountain Rescue party and escorted to control for rewarming . They were then able to make their own way home