I can't answer that, but there was an early shipment from B&N here in the US. What is up with the limited release there in the UK? Which is currently sold out. I would just bite the bullet and order it from the US. I had to order the "Spook's Battle" by Joseph Delaney from the UK. The US is a year behind in its release dates for those books.
It's a turnabout on this book - usually the UK gets all the books WAY before the States! If I can't stand the wait, I usually come here and see if it's available, and if so, order - it's worth it to me if I really want it to pay shipping. So I suggest you order Eclipse in the USA and you'll have a leg up on your friends!!