I just received an eMail from HMV stating that the limited numbered box set has been discontinued and is no longer going to be available:
Quote from: HMV
We're really sorry, but the suppliers have now informed us that this item has now been discontinued, and they are not planning to manufacture any further copies.
We are going to try to see if we can get the item from an alternate source for you for a further 30 days. If we aren't able to get any more stock, then we will send you another email to let you know that your order has been cancelled. If we are successful we will let you know when the item is on its way to you.
I take this as the studio has decided not to release it, but it could also otherwise be taken as there's been some supply problem somewhere down the line and they may still be able to get hold of it from elsewhere (Ie, probably a European import instead)