Hi,
Whilst I can't identify the decanter for you, (sorry), I have spent some time this morning researching, Creative Energies, Fire & Sea, Dartington...... What I have found is that the stopper looks very similar to a Kastrup Glasvaerk one. Have a look at this site, which I think is Nics?
http://zeitgeist-i.com/G-Dk-0075.htmlwho no doubt will be able to add much more.....
I am finding my interest in decanters has been piqued recently and would very much like to know who made yours.
Hope its resolved.....
Sharron