The entire collection is up for grabs as far I know I saw a copy of the DVD in Woolworths in Crouch End yesterday, although that might be any use to you. It simply be that your local stores are out of stock, it may be worth asking at the counter.
Its not part of the "2 for 1" deal so that there is an even number to collect. They shoulda waited for Die Another Day and then done the offer. Froggequene must of seen a rogue copy from prev releases. if you find one GRAB IT and use it as part of the offer & see if you can get away with it. I noticed it to. Even the web sites state its release date as T.B.A (To be announced). See play.com for example.
When I was out shopping today, I went into a few places and I couldn't find it either but I didn't have time to ask why but have you tried ebay? I tried it just out of curiosity and it threw up loads of stuff.
I've got it, but then i've just bought the entire 007 box set that was released at the beginning of November. I guess that's not much use if you've already got most of the films on DVD. Sorry, i suppose you'll have to wait until they decide when they're gonna release the single DVD. :(