Thanks all for taking a look.
My eyesight hasn't been great lately, I will take a closer look in daylight, however, I think M may be right that the glass is indeed an amber colour. I have attached a slightly edited photo, which I showed earlier, which may show a little more closeup detail.
Its proving tricky to determine if the inclusions are either a gold powder/dust or mica. I did also ponder over the possibility of
Polveri...although I see there are varying descriptions of this process/technique. Would I be correct in thinking that Polveri relates to the use of powdered glass..? Again, not sure if that's applicable here or not.
My first, possibly hopeful thought was perhaps Copier and Leerdam too, I've also not found anything which marries up. Interestingly, WMF was also a thought, again no luck on that front, I did wonder if perhaps its the shape that's reminiscent of WMF rather than anything else. Unfortunately, I don't have a copy of the WMF book.
Hope the attached picture helps a little, I will try and get a better image of the inclusions tomorrow in daylight.
Many thanks.