Well, my copy of The Night Child was ordered at £8 and they reduced it to £7, and then put the price back up to £8, and according to the sticker they only charged me £7, so I'm guessing HMV's price promise does work like that too.
Although I do have my copy of ZFE ordered at Amazon, and am kinda hoping they reduce it to £11 like HMV. I did click the 'tell us about a lower price' link and filled in the form, but they haven't reduced it yet (and I did it on Friday
). Perhaps a few more people who have it ordered at Amazon should do that too *hint*.