Me again, with a couple of extra points.
The "American gentleman" goes by the name William Gaskill and, should you wish to contact him, the PCA site is: http://www.paperweight.org/
- in the "Contact Us" section, William's email address is given.
I have checked his articles (3 of them) on English Bottle-Glass items in the PCA Annual Bulletins and one point is about the metal used for the flower decoration. I had used the common and well-ingrained term "silver foil", but William has investigated deeper (quite literally!), by using an already damaged piece, to get at the actual metal and test it. It turns out that it is not silver foil but very thin thin foil.
There is now some agreement that items like yours (and mine) were more likely to be Mantle Ornaments, rather than Doorstops as has often been suggested over the years. With the shape, weight and the centre of gravity of examples like ours, there would have been little chance of holding back a solid door! And William Gaskill puts a good argument for most of these items being factory-controlled output, albeit to "working class" customers, rather than out-of-hours occasional friggers or whimsies. He rightly points out that, judging by the numbers of the surviving examples, it would have meant a LOT of glass "walking out the door", had they been "out-of-hours" pieces.
Amongst the factory marked pieces one has come to light with the mark (in exactly the same style as the Kilner ones) of "Redfearn Bros Bottle Manufacturers Barnsley". That one has "tear drop" air inclusions, which was also a style used at Kilner. This suggests that we need to keep an open mind about whether tin foil flowers might have been made at places other than Kilner. But for now, the evidence does lean towards John Kiner and then John Kilner & Sons, ranging from about 1829 to 1845 or perhaps a bit later.