odowdh said:

3

or so years ago on a trip to Italy

from Sweden (röddby (Denmark) to puttgarden (Germany)) I

bought a block of very dark chocolate which was brilliant – not sweet at all but

very chocolatey. It was a substantial block with large ‘squares’ and the paper

wrapping was a black background. I seem to recall it was German…

When you say “block” do you mean that in the usual English sense of the term – i.e. an amount of chocolate both considerably in excess of what would reasonably be considered a “single bar” and considerably thicker than it? A typical bar is usually 50-100g so you need to get to about 500 g before it's really a “block”. Such blocks are usually at least 1cm in thickness, possibly more. A bar, by contrast, is usually thinner, somewhere between about 3mm and perhaps 8mm. Some large bars are as much as 250g. From the fact that you mention “squares” I suspect you're talking about an ordinary large bar because most “blocks” aren't moulded into squares. Can you remember any pattern on the squares (this is a very useful way to identify brand)? And can you give a rough estimate of the size in g?

Was the wrapping a solid cardboard box with inner wrapper, a paper wrap for a foil insert, or simply a paper wrap? Can you remember any other colours or details that stood out on the background? What about the colour or font style of the lettering?

You say you got this from the ferry shop? Is it selling primarily commodity items, or a purposeful high-end chocolate shop? (Be sure to distinguish, too, between shops  designed to cater to tourists with lots of “local” products that superficially look high-quality but in actual fact are fairly mass-market, and true specialist shops whose interest is quite obviously and centrally on the chosen product of focus.) I should note that it's not necessarily a given that tourist-centric shops will stock only commodity brands – e.g. there are several shops in Rome airport selling Domori, Amedei, etc. However it's fairly reliable that the tourist shops will stock only products available through distribution rather than extremely local micro-producers living by word of mouth.

All this being said, the chances are fairly high that what you bought is a second-sourced bar manufactured by someone else – obscure brands that never seem to reappear tend to be of that type, in which case its actual origin and brand could be, again, almost anyone.