Eggshell, English or other European maker?

Unable to find English maker of three eggshell porcelain cups and saucers. Hardly any references in standard literature to English eggshell, and even V&A were stumped... The photos below show one of the pairs. The flower patterns differ with each pair. Unmarked, except for base of this cup which has '988' carefully painted in iron red in centre, in unusually large numerals. Very much Japanese/Aesthetic Movement taste, down to gilt-speckled handles and peculiar waisting of the cup, like Japanese hand drum. Cup rim diameter 7 cm/2.75 inches; height 4.5 cm/1.75 inches. Saucer diameter 12.7 cm/5 inches. Thinness & translucency exactly like Japanese eggshell. Grateful any suggestions/leads.

Difficult to tell from the photos, but is the decoration hand painted, or hand coloured transfer printed?
It could have been a commission - 988 would be the pattern number - and the porcelain blanks may have been bought in from another manufacturer (eg, made in Japan and decorated in Staffordshire).
As there's no maker's mark/stamp then you're limited to the style of the handle and shape of the cup to try to identify it, but that will probably not tell you who painted it.
As there's no country of origin, it's probably late Victorian or turn of the century - before import tax.

Hi Naomi. Good suggestions! It had not occurred to me that they could have been made in Japan and shipped here for decoration. They certainly 'feel' more Japanese than English. Were Japanese eggshell banks exported in that way? I am not sure about the transfer angle. They look hand-painted, and each is different not just in the colour of the flowers, but in the shape of the twigs and leaves. However, with the aid of an eyeglass, you can see in a few places a very fine gauze which has been overpainted in enamel. All in all, they are still a puzzle to me. Maybe 'English/European eggshell' would make a good research paper for soemone!! (I have just acquired a 'K' series Brown-Westhead, Moore Victorian cup that is also of eggshell thinness, though not the saucer.)

Just guessing about whether they were Japanese blanks - they could be continental.