I think that I saw some Brooklyn Brewery beer in the window of Carvill's of Camden Street this past Saturday. I don't think that they had the stout, but I didn't check everything. If they have the Black Chocolate Stout, then I highly recommend trying it.
I don't know what to say about the metric labeling issue-sounds like a line of BS if you ask me. I've got a bottle of Brooklyn Brewery Black Chocolate Stout that I picked up in Denmark last week with a 12oz label and no reference to metric measurements at all. Maybe the Danes have smuggled it in?