There is no custom duty for computer hardware in EU. You have to pay VAT if you import it from outside EU. VAT is different in different EU member states.
I believe the right code is 8471410090, but anyway, If you are in EU, you dont pay custom duty, but you pay VAT (17-27%, depending where you live).
Here people seem to speak about custom duty/tax when it is in fact VAT.
Well then you should be pretty sure you paid it ready while purchasing EU-assembled miners with the chinese parts;-)... So there is actual question inspite of how it is named - how much do they overpay for their miners to the gov. Looks like when you pay VAT you paying for your miner twice as the company assembling your hardware ready paid same VAT for the parts that they ordered from China right? Or maybe i misunderstanding EU customs law - please correct if so.