Visited 3rd August 2004: Carnan a'Ghrodhair is easy to get to, but not really worth the journey. There's nothing much to see of the souterrain, but if you're interested in Second World War architecture you may want to ponder the Home Guard bunker that's been planted on top of it.
This was my first visit to a souterrain, and based on what I've seen so far I'm a bit disappointed.
The National Monument Record makes Carnan a'Ghrodhair seem rather more sexy than it is on the ground:
A souterrain was found during the last war during the construction of a Home Guard gun emplacement or look-out post.
When digging the foundations the workmen struck a flagged floor with a large stone in the middle which, when removed, revealed a passage-way leading down at an angle a distance of some 20 to 30ft before opening out into a beehive cell about 6 or 7ft high... About 35ft east of the emplacement there was a slight de- pression with possibly a few stones in it, which seemed to mark the site of the cell.
Mind you, it does warn you that, "the entrance to this souterrain, within the look-out post, is almost fully blocked with rubbish, making access to the chamber impossible". Apparently the passage was still discernable in 1969.