just had a look in Reynolds book, and certainly all of the pieces of this pattern that he shows do have the central pale area to the leaves, so it does seem to be a Walsh feature that is constant in 'Fruiting Vine'.
Blown stoppers have been around for a very long time, and the shaft and globe shape doesn't help to date the piece, unfortunately. However, it may be that the lack of deep mitres and profusion of shallow wheel cutting might point to a more recent date than you are suggesting, but I'm really only guessing.
Decanters are so commonplace, and produced with such a profusion of copied earlier styles, that without a name or very well known pattern, they nearly always prove impossible to attribute.
You don't comment on the extent (or lack) of wear - and although not a reliable method of assessing age, it might suggest either C19 or perhaps C20, and a base picture might help to suggest whether of some quality or not............ i.e. is there a quality cut star, or simply a plain bottom.
But as I say, I've a feeling you're onto a hiding to nothing with this one, unfortunately, so fill it with a good dry sherry and drink away