Update 2: Well, the melting tank arrived back 3 days ago, and I noticed that I could not keep chocolate in a good crystallized state. It appeared to be getting too warm - and sure enough, ten minutes after getting the chocolate pre-crystallized, it goes out of temper and very liquid.
So it appears it has a faulty thermostat now. UG! My other Mol D'art 12l is fine, i have no issues with that one, but with this one: I guess once a lemon, always a lemon. I let the milk chocolate in it cool down after switching it off, stirring - took about an hour - and got it back to tempered state (lovely shiny test and all), checked with thermometer which showed 29.8 degrees C, and what did the thermostat say? It clicked on and off at around 18 degrees...so looks like this one is going BACK to Mol D'art. And this is a brand new machine, twice faulty now.
I am also cancelling my order for 2 x 6l Mol D'art melting kettles, as I have totally lost faith in this brand, so if anyone knows a good RELIABLE brand of melting kettle that would be available in 230v (New Zealand), please let me know.