I think I know why: the main competition is (IMHO) the Audez LCD2, in the US that headphone is $1145, which translates to £684.81. Of course we would never see that price since the LCD2 is made in America and we would have to factor Import duty and VAT into the equation. Because of that the UK price, from a UK dealer, of the LCD2 is £1025. The HiFMans are also competition but are also US based so, again, there's no local alternative. They're price matching to planars that what we can get in the UK (all imported from America) and the price has nothing to do with import duty or VAT; pretty $hitty I think.
Can't you buy them somewhere else in Europe?
Pretty sure Hifiman are available in EU in the $=€ currency, sometimes even less. Audeze was hard to find for reasonable prices that is true and so is Oppo.
Regardless, won't derail the thread any further. I am just throwing it out here.