I have finally found someone selling the same slightly wonky shaped kluk kluk decanter but with a slightly less-flared top than mine and smaller overall, but with the same-shaped stopper!
But... the one I have found
is clear glass with enamel designs and is described, interestingly, as "Antique Dutch Danish Mosser Art Glass Pinched Decanter Perfume Bottle with Crown Stopper HOLMEGAARD Enamel Decor"
which doesn't help much with finding out who made it. The seller, however, is in The Netherlands in case that is useful in pinning this down... but then I find another decanter with similar size/decoration and same stopper on eBay with a seller in Huntersville, North Carolina, so perhaps that's not helpful!
Can anyone throw more light on the origins of my decanter please, and possibly the one linked (without being critical of the seller)? Ta!