Indeed, and their various translations of Bray have all been held to be suspect.
But - to go to a point Mayner made which I had omitted to remember - a private siding would not, indeed, have had any sign on the railway at all, let alone a bilingual one. These were only for railway signage and name boards, particularly in the passenger parts of stations.
By law in Ireland a private company (like a mill) isn’t, and never was, under any compulsion to have bilingual signage, whereas a state utility (like post-nationalisation (1950) CIE) was.
The GSR was never a nationalised utility, but in its station signage it behaved as one, although there were many examples of stations which lasted well into CIE times with original pre-grouping English-only signs.
So for “Mol’s Mill”, the oval device of the milling company would, if strict accuracy is preferred, really be the only show in town.