hey rob - the cheapest pre-order is £409 i think with Komplett.co.uk but they've sold all of their all allocation for Day 1.
However - argos are still pre-ordering theirs - they've not yet sold their Day 1 allocation and they're your best bet @ £424.99 (do a search for 568 3707 - cat no)
I've got mine with both companies and guaranteed too.
If you struggle to find any pre-orders - give me a shout!