I have had the car serviced several time and had Freon added by a certified AC Mechanic. The gas has escaped again and I was told that they could not find a leak in the engine bay using dye and a black light. I was told that the leak was behind the dash (possibly the evaporator) and would require the removal of the dash. Does anyone have experience with this and a possible suggestion on where to take the car (AC specialist, Jaguar Specialist, Dealer). I am at a bit of a loss. Thanks