Not that I want to poop on your pancakes, but keep an eye on camelcamelcamel for an idea of the real discount. Ie.
About 32-33 quid is regular for the last year or so, and down to 27 quite regularly.
I've almost emptied my stock of whisky so I need to either re-stock or emigrate!
EDIT: Sorry, i meant to say, summary is: Amazon are disingenuous arses!