this is why my petrol doesn't have it yet... got Webasto / Eberspächer on the Octy and wouldn't miss it for the world. Great piece of kit. Press "go", wait 10 minutes and the car's starting to get warm.. or wait 20 and then it's toasty. Awesome. Also drinks about 1l/h, which is acceptable in my world. I can turn it on from the office, get ready to leave, heed nature's call, sort myself out and by the time I'm downstairs it's really got a head start. Or at the airport just set it to be done 30 min after arrival time and when I get there, the car's warm. Been so long since I needed to do that...
There is a kit available online to convert from just a heater to a full aux system.