Do you think it's possible to just pre-order it on Amazon DE and be able to send it to the UK? After all it's the exact same packaging & phone that'll be available to everyone right? UK buyers could possibly get it cheaper by ordering it from Germany for ?480 instead of the ?530 that is listed in the UK - not sure if duty will be charged though so that's one thing to think about.
There are no taxes within the European Union. When you shop on Amazon-de and ask for it to be shipped to the UK, they'll adjust the VAT (from 19% to 21% or whatever it is now in the UK) and that's it. The only thing you may have to pay is the shipping costs which vary according to country.
For example, to Portugal they charge 7€. But to Belgium there's free shipping (I had mine dispatched to my sister in Belgium).
But no matter what, it will still be cheaper than ?530 I think.
The only thing you should be aware, though, is that the charger you'll receive is a normal European charger. But I don't think that's a big deal as you can continue to use whichever USB charger you already own. Apart from that, it's the exact same phone
(Just so you have an idea, my Lumia 800 and 920 came from Germany, my L620 from Belgium, my 820 from the UK and my 1020 from Finland. So there's absolutely no problem buying phones around Europe as long as they are unlocked as they almost always are
)