During the late 1950's Park Royal produced cabs for various AEC chassis at volume production rates. Here is an example of a fibre-glass cab on an AEC Mercury chassis.
I am uncertain of this cab but my guess is that it is a Park Royal cab, similar to the one above, mounted on a Maudeslay chassis that would have almost certainly been a badge-engineered AEC - and probably a Mercury. It was probably destined for the commercial motor show in 1959. Does anyone have any knowledge of this vehicle?