A second research Google on "ROMAN ROADS" allows of discovering lots of sites treating with the roman ways and with the roman sites among the British ones.

And, after numerous explorations, one finds to the address:
http://www.tlysau.org.uk/en/item/12309 

  and under the title: "Aerial photography of Y Gaer, “Roman Trackway”, Aberysgir, 2001", the picture here against pertaining to 411 pages of 6 photos of which the copyright belongs to "Royal Commission on the Ancient and Historical Monuments of Wales. 

Hold out therefore! The main building trade, in the form of "U" square, it has been built on the basis of an old roman "statio"? ...

And, skimming through the 2466 photos of the "Royal Commission on the Ancient and Historical Monuments of Wales ", one can see the photo here against (site of Walton) presenting a dark, comparable trail to that of “Taxo d’Avall”, and considered it also by the Welsh ones as a "roman trackway".