This pretty 7-1/2" plate is a good example of English Floral Chinoiserie. There is lots of underglaze cobalt blue, and pink and orange flowers with flitting butterflies.
The plate has Ridgway's striking Royal Arms Mark on the back. Because that form of the Royal Arms wasn't used after 1837, and John Ridgway's pottery began operations in 1830, the plate can be dated 1830-37. The hard-to-read initials JR are on the ribbon at the base. The pattern name "Constantia" is shown. The pattern number 5258 (with a 2 underneath) is handwritten in red. There is also a blue 7 and a red 6, which are likely a workman's tally marks.
The plate's condition is very good. There are no chips, cracks, or repairs. There is quite a bit of crazing, and some light discolorations. I have tried to show this in my photos.