We know it's made by BG, and though I am not familiar with where the denomination "2.5" is used, I would begin with those countries and maybe something at sea... and I would discount anything with the name Napoleon but, maybe look into Neptune, or or the casinos in countries that have used a crown as part of their logo/name... and definitely employ the process of elimination.

Maybe "crown" as part of the name should be searched as well.