Windows 7 Pro OEM = 82 GBP ex VAT Windows 7 Home Premium OEM = 55 GBP ex VAT Large difference! There are a number of Win8 upgrade restrictions in the UK AFAI

Windows 7 Pro OEM = 82 GBP ex VAT Windows 7 Home Premium OEM = 55 GBP ex VAT Large difference! There are a number of Win8 upgrade restrictions in the UK AFAIK including you can only upgrade retail PKUs (not previously purchased OEM ones). The deal is 25 GBP for the upgrade.