Well, this has been an interesting side-quest!
Having been told that the Polish version was 'full cinematic', my adventure took me to Spain ... where no-one had ever heard of this title!
So then I found a 100% English version (ie including manual) in a number of Slovak and Hungarian online stores - with Hungarian ones being around 10 Euros(!!). However, they do not ship outside of Hungary... (someone probably forgot to tell them they were in the EU). The Slovaks did, but accepted only a wire transfer of the funds (which at my bank would cost nearly 40 Euros, plus 29 Euro for the courier shipping, plus 28 Euro for the game itself) - no paypal or cc. There was an asian retailer that would ship to EU, but warned this could take 'a while' and might get nasty if someone decides to charge import VAT when it arrives.
At this point, I was rather tired of Googling for DKS, especially since most of the results had the word 'torrent' in them, and after all my sisyphean efforts, this was beginning to seem tempting. I also considered hiring a mercenary to go to Larian's HQ, break in, and grab a few DVDs, on the offchance that maybe one of them would have DKS in English.
And then I considered the most ludicrous idea of them all - that is, to download it off Steam, and betray all my principles. But fate stayed my click-finger, and by chance that same evening, I found that the Scandinavians all had English versions! So finally bought one in Finland for 24 Euros plus shipping. Just finished installing it now. @Larian - how many XP do I start the game with, having completed all that?