You can pre-order The Guitar Hero 2 Bundle for the PS2 from HMV for £31.99 delivered, using the discount code below. This is a great price for this item which will be released on the 6th of November. But here's the thing - the HMV website does not actually say what is in the bundle, but one can assume it is the game and the guitar - as shown on amazon in the "bundle" deal, for example.
If, by some mad chance that it is not the one with the guitar, simply cancel your order before the release date, but I really don't think this will be the case.
(Note the image I have used is taken from another site and is for illustration purposes only.)
Promo code: DG6564