antique flow blue china, set of 10 cups and saucers, unmarked English Staffordshire 1880s?

Uncommonly large nice set of ten matching cup and saucer sets, antique flow blue china, not marked at all that I could find. They're ironstone or semi-porcelain, almost certainly Staffordshire. These are the old fashioned large cups and saucers, with cups about 3 1/2" in diameter, and 6" diameter saucer plates.

We'd guess the age at about 1880, give or take 10 years?  Without question before the US tariff laws of 1891, when law would have required export pieces to be marked with the country of origin.

There is crazing, and a few small glaze pops at the rims of most of these pieces. Nearly all pieces show at least slight discoloration / staining from use.