The question was asked above about livery in Ernie's book. Those are maker's photos, where they painted wagons (or carriages or locomotives) in varying shades of black, grey and white, with ironwork usually black, to emphasise detail in official (black and white) photos. This would not have been the livery they entered service in - manufacturers photographed them like this, and then painted them in the actualy livery of the customer's railway. In the case of the WLWR this was medium dark grey all over with white lettering. I THINK - but can't remember where to call up any hard evidence - that the grey used by the WLWR was probably not unlike the (later) LMS wagon grey in England, with roofs a very slightly lighter shade.
This was a maker's photo livery. Grey in traffic.