Well spotted Hugo, it is William Arthur Maddocks, who built the cob which produced revenue through the tolls and which created the slate port which was named after him. The carving, which has a long bench attached to it, is situated at the western end of the cob but you only see it from the train unless you turn off the road. There are good views of the reclaimed land and also the Moelwyns, Cnict, Moel Hebog and the Snowdon Horseshoe in the distance (see attached photos).