This cairn is visible( with binoculars) from Ty Illtyd chambered tomb. The line is just to the left of Allt of Esgair as seen here. No idea if it's intentional or not, but the more I study these Breconshire monuments, the more these improbable sightlines reveal themselves.
This same view can be seen, in reverse, on the Ty Illtyd page, in an image by the postman.
Postman's photo. Eglwys Faen cairn would be approx. centre of this image, on the skyline. The hill to the left is Allt yr Esgair, and the lower one beyond is the Myarth, with Mynydd Llangatwg and the cairn the far skyline.
Ah, that's interesting. I guess though that the hills are so full of monuments that some of them must line up accidentally. But I wouldn't want to say that there isn't intention - these buggers were too clever for that. I ought to make the effort to get to Allt yr Esgair (and Ty Illtyd) sometime soon.