Ive just fitted a shop bought waste oil burner BAIRAN BRAND, to a oil fired warm air cabinet, and took the time to take note of how its done, its really simple, and Adrian you could do it without a degree, if you could get a riello burner i can literally talk you through the conversion,the only bit you need is a nozzle and you drill the existing holder to suit so no machining, and no PID controller or nozzle heater, get the cheapest,smallest deep fat fryer, and you have a heater element,controller (90 degrees),overheat switch, burner done