Porcelain. Bristol or possibly Plymouth?

Sold to me as 'Pinxton' but it clearly isn't. I am wondering if it could be early Bristol or even Plymouth (fingers crossed).

The jupter 4 mark was used by Plymouth, but Goddens says underglaze blue,
or overglaze enamel.

Plymouth porcelain would be exceedingly rare indeed. Bristol only a couple of notches down the scale. Something of course, that you already know.
Given the value and the time scale and the inherent possible forgeries blah blah the only really cast iron certain way would be to take it to one of them very high fallutin auctioneers and ask them, for their judgement. ie pu it to the market
It looks pretty good…..But.....but....but

Thanks for your replies. I think it's a Victorian copy of something but the Jupiter mark intrigued me so was worth a buy. If only...