Hi. Take the parcel shelf out and then take the boot carpet out. Now take the spare wheel out and have a good look at the boot floor and check for any holes. If you cant find any get a torch then get in the boot. Have someone close the boot and spray water from a hose or watering can around the boot edge and the rear lights. Follow where the water is being sprayed with the torch and you should see where it is coming from.
Simon.
October 2005