John Ridgway's wares are always very high quality, and this soup plate is right at the top of his production. The large polychrome piece is 9-3/4". It was made 1835-1840 at the Cauldon Place Works in Shelton, Hanley, Staffordshire.
A previous owner found it beautiful enough to grace his wall, but used a tension wire hanger which was too tight. The hanger chipped the plate in 2 spots, which I have given you large photos of. The only other flaw is a flake to the red-orange enamel of the lowest central flower. No further chips, cracks, crazing or repairs. The plate rings when tapped.
The plate is marked in green on the back with the British Royal Arms, Imperial Stone China, and the initials JR. The pattern number 5054 is painted in green, and there is also a tally mark in green.