Hello, I hope the following assists you. You can't retrofit an original auxiliary heater but there are plenty of aftermarket options. I personally have had experience in an Arctic climate and fitting fuel fired heaters or parking heaters was an almost daily occurrence in the workshop. Depending on the features required the best option is the fuel fired heater that is programmable, this way you can set the heater to be on using the timer options, this option heats and circulates the coolant and has the heater blower on a slow speed to warm the cabin. An example of the best system is www.webasto.com/gb/markets-products/car/retrofit-parking-heater/ this system can even be activated using your mobile. Another option is to have DEFA system installed, this runs off mains electric, you get the option of having a fan heater and engine coolant heater plus the system keeps the car battery charged. An example of this is http://www.defa.com/en/automotive/warmup/find_your_engine_heater/ Both these systems can be used with your car with no problems. The Webasto fuel fired system can be operated anywhere without the car needing a power supply but in terms of reliability the DEFA is more reliable as it doesn't rely on fuel burning and is easier to install. I hope this helps but if you need further information let me know and I'll reply as soon as I'm able to. Best wishes, Sean.