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I'm sure somebody does know who made the Carnaby-alike Japanese glass, it's just not me.
I've handled a large tall yellow vase, and a very short, wonky, lilac, gulvase-alike piece. (That had the same kind of unclear and wobbly divide between the liner and the colour at the rim I would not expect to see in anything Scandi.)
Both pieces were wrong shapes and sizes for Lutken, and lilac is a wrong colour.
The gulvases were also made under license to a company called Cascade in England. They are not lined, and either turquoise-blue or amber.
There really isn't anything about a bit of glass you can call fake - only claims made about it.
When you are holding a bit of glass, you are holding its own original self and all that matters is that you like and enjoy it.