mine is not a parafin version, its the wee electric fan heater the make is parasene and its called the 'frost fighter' works a treat the temp in my van currently is 11c and outside its barely 1c
I use a greenhouse heater from homebase now and so far so good, its 27.99 and it has a frost setting on so you can be sure it wont let the temp inside van go below freezing. its drip proof too so if any condensation drips it wont trip your leccy.
Same as below Paresene frost fighter heater my van hasnt frozen inside also experimented with a dehumidifier in van as well which has reduced condensationJust the external bumber ports that froze solid thank god for my trolley systemroll on tommorow