Typically, the hand-painted pattern in cobalt blue is supposed to imitate Chinese porcelain of the same period. There is a pagoda on the left, a bridge, islands and a strange tree, all copied from Chinese designs.
However, there is an anomaly (see arrow) at the top left - a windmill which is clearly a post mill - not a feature of Chinese landscapes. The painter and designer of course would not have known that - and neither would the customers in all likelihood.
Who was the painter? Well we know women and girls painted porcelain at this time. It was light work and regarded as a respectable working-class occupation. For example, from documentary evidence, Mary Redgrave (born 1761) is known to have decorated porcelain over at Lowestoft on the Suffolk coast.
Of course the post mill was probably the pattern designer's idea, but is it the work of a woman or girl painter? Notice the simple circle at the top, supposed to represent the sun and the naive way a few birds are depicted as a kind of flattened letter m. Remember also that women of this period were quite likely to be adept at fine needlework, so the painting may not be the work of an adult.
Of course it's impossible to say who painted this saucer, but I prefer to think it was a girl who passed by a post mill on her daily walk to the porcelain factory. I like to think she wasn't just copying a designer's pattern, but was familiar with the mill herself. It would have been a landmark, maybe the mill where the local baker bought his flour
It's a narrative, if a little fanciful, but it fits what we know, although other narratives are obviously possible. Historical narratives tend to be like that. We can't test them by altering the past, all we can do is uncover more facts or prove links between previously disparate facts. I don't see that we can do much more as long as we build the narratives transparently and don't leave out known facts.
I'm not so sure this restriction is such a huge gulf between history and science that is sometimes claimed either. After all, climate scientists want us to accept a narrative that doesn't even fit the facts, such as the fact that it isn't warming as their theory requires.
So my saucer narrative may only be one of many possibilities, but I'll stick with it because it fits the known facts as well as anything else.