Argos have Windows 7 Home Premium E Edition available for pre-order again at the £49.99 price.
But it takes a little work, on their site it's listed as £79.99 but it clearly states that if you order by the 09/08/2009 then there is a £30 discount.
The only way to get this is to phone Argos directly and explain to the CSA on the phone what you want, it's product code and why you're calling them (ie the price on the site is wrong)
Also make sure that they don't charge you the postage fee, my CSA tried, but I pointed her to the website again and she took it off no worries.
Very helpful, if you get no joy at John Lewis then this looks like a good option.
PS I know that Microsoft have said that their not gonna release the E edition anymore, but you should still get a Full retail copy from this, if not there's gonna be hundered's (if not thousands) having a good old moan.
PPS The product number is 573/6623 and the phone number I called was 01785 250000 Ask for sales (This is from the SayNoTo0870.com site)