i have a WEBASTO diesel heater, its german like the Eberspacher, its a 24V unit, BUT i have a 24 V - 12 V converter
all you need is a fuel source (many use go kart fuel tanks) and your ready to go
it came from a german specialist, he assured me it was working fine, ive just not fitted it yet
it was brought for my VW campervan, but as i dont use it int he winter it was a idea that will never be used
if any1 wants it, make me a offer, keep in mind they go for 150 - 200 quid on ebay
if no1 wants it, ebay here it comes