I did get a promo email (can't remember if it was from Sony or Waterstones now) last month which announced the Reader being offered for sale by waterstones and that they'd have 2 weeks head start before it was available elsewhere (including the sony stores in the UK).
I'm pretty sure the same email said that waterstones own website would be selling ebooks from 25th September (date the rest of the uk is able to sell the Readers).
Though you'd think the ebooks would be avialble whenever Waterstones were able to release the Reader, so I may have just imagined that last bit.
Oh, and Brits are much like everyone else...only more British