1 option is to remove everything from the boot and get someone in the boot with a flashlight. Use a hosepipe with medium pressure and spray over one area at a time covering the whole boot area/rear end. the person inside the car must have a look with the f/light where the leak is.
Hopes this help. We did it with my fathers ford focus and found the problem within 10 minutes.
REGARDS
Daniel Coetzee
May 2008
howtomendit.com for free repair help, information and advice.
