Hi,
Is the factory that made the plate still in business? If so, drop them a line and ask about the design as many of these would have been retained in the company records.
It would be of great assistance if you could somehow let us see a photo of the plate. Who knows, there may be an antique plate collector amongst our readers who may be able to assist you, especially if he/she could see the design in its actual colouring.
Rgds,