Best of luck for tomorrow. It is a fantastic diet, but the first week is the worst. Get through that and you'll be fine.
Tips: have the Nurofen ready for headaches around days 3/4/5. Buy some low-salt Bouillon from Sainsburys (prob specialist food section) in case you get really hungry, it gives you a bit of a savoury boost, be strong 'til your first weigh-in - then you'll have all the incentive you need.