Thanks - great pics
It looks as thought the design has been engraved into the glass somehow (I don't know much about these things - for example could it have been hand done? or done with a stencil of the design of some sort ? Hopefully someone who knows more about these things might be able to help), then gilded over with gold (and silver possibly? could it be silver that has tarnished ... it does that and then appears grey or black).
The polished pontil mark and gilded fire polished rim to the vase make me think English or French as you have said.
I'm wondering slightly about Stevens and Willliams - but only because of an extremely tenous link in my head - I have a small 'alabaster range' S&W cocktail glass that is very bizarre in that it has an engraved grouse (and another dead grouse) on it and then has been gilded. The engraving on mine though is quite umm, sort of cartoonish in a way. It's not a cartoon depiction, but I think because it is quite simple and such a strange topic it appears that way. (It's a really very weird piece and I've never been able to work out exactly who or what it was made for - never seen another).
As I say, a very tenuous link, however the shape, the opaline and the large polished pontil mark could also come from S&W, which is why I mentioned it.
Have you searched the Black Country museums website for a shape match? I don't recall anything in the engraved style of decoration being on there though as I would remember it because of my glass.
~Sorry I can't be more helpful.
m