Taxman,
I could be wrong, but I was told that the PEt heater and supplemetary heater are 2 different things. My car (2005 GT 2.0TDI) has the PET heater. I know this because if I set my heater dial to 75% or more of maximum heat, and switch OFF Econ, then I get warm air coming out of the vents within only a couple of minutes. This morinng for instance when the car was iced up, the windscreen was clear within 5 mins or so.
As to the supplementary heater, I think this was an option for Scandanavian countries (where it get really cold), and consisted of a plug socket mounted in one of the bumper grills which you plug into the mains. Please somene correct me if I'm wrong.
As to your main question, it's my understanding that only the 2.0 TDI's have the PET heater ?
GT-TDi - Almost fully loaded and loving it !