Georgian Bat Printed Porcelain Cups and Saucers and Creamer

I found these interesting, very old cups, saucers and creamer. I have been looking them up, and the cups are Bute shape and are Bat Printed with a rather crude design of a Mother and Child. Bat printing is when the design was stippled onto a copper plate then a sort of glue and isinglass were transferred to the porcelain. It leaves a dot or stippled effect, which these have, though I think far too much ink was used on these items! Anyway these cups and saucers date from 1800-1820. I have noticed that some of the cups and saucers are much yellower than the others. I'm not sure why, but I'm trying to find out! All these 200 year old Cups and Saucers for £3.50!