There is a new deer fence, but I do not think that is a problem. There is a (sheep) path alongside the fence, boggy in places.
I would change the route description:
Follow the deer fence to the left of the house...:
... to its highest point and then head east aiming for the point where the Allt nan Coisiche changes direction as it emerges from a ravine and before it goes into the box canyon (GR NC070037):