Hi Duncan,
The original architectural drawings were available for purchase online, but the building was never constructed to them as they were based on broad gauge, the walls, roof and length of the actual finished building were modified. So I based on physical dimensions and photographs.
I had the building constructed of laser cut 6mm and 3mm mdf which I produced on CAD and clad it inside and out with moulded stonework sheets and features that I modelled and 3D printed.