Coed y Moch Lodge can be briefly glimpsed in “The Last Days of Dolwyn” (aka “The Women of Dolwyn”), a 1949 British drama film directed by Russell Lloyd and Emlyn Williams and starring Edith Evans, Emlyn Williams and Anthony James. It is also the first movie appearance of Richard Burton.
Dame Edith Evans is the actress shown opening the gate.
(1) The roof goes right down to the bottom of the window in the film while Coed-y-Moch stops midway in the top panes. (2) The horizontal roof (and the building under it) is missing. (3) The pillars supporting the arches are round on the film but squarer on the actual lodge. (4) There looks to be a building in the distance, but there isn’t one by the actual lodge.
I do not know of any other building in the area which is like Coed-y-Moch, so perhaps there was some painting on the film to change the appearance afterwards. The other option is that the building was built on a set and made to look like the lodge, as the village of Dolwyn was partly recreated as a set, it’s not out of the question that they built this too.
If you do know anything about this, please let me know.