We were actually looking for Coat Menez Guen (which we never found although we must have been within inches) but found this, Coat Luzuen instead.
Having found this one, still thinking it was Coat Menez Guen, we struggled to make sense of Aubrey Burl's notes about it in 'Megalithic Brittany' before realising he was describing a completely different monument.
Coat Luzuen is a grand, if neglected monument standing near the edge of field. There's a little break in the hedge for you to get through to reach it. From what we could see through the tangle of vegetation surrounding it, it had two large flat capstones, one I guessed was 4 or 5 ms long.
You could get it to its quite big chamber easily and I sat in there for a while, out of the drizzle, looking at the tendrils of ivy curling their way around the stones.