This pretty floral tea plate, 17.5cm wide, just says Made in China on the back along with some Chinese characters.
This is another pretty floral tea plate, 15.5cm wide, made by Johnson Brothers Ironstone.
This simple white saucer, 17.5cm wide, is from Donna Hay Homewares.
Here are two Sampsonite Churchill plates. The tea plate, above, is 17.5cm wide and the salad/side plate in the photo below is 23cm wide.
This is a Wood's Ware "Beryl" salad/side plate, which is 22.5cm wide.