I've done exactly that and ordered all 6 titles from amazon.es. With their flat rate shipping of EUR 4, the total for all 6 items shipped to the UK came to EUR 116.54 (£82.60).
Given that they're all being released on the same date, they will hopefully be sent out properly packaged in a box.
This is certainly a better price than any of the UK retailers are offering. In fact, it's probably the best price, so far, of any of the EU countries.