Has anyone used one of these or similar?
http://www.ebay.co.uk/itm/12v-600w-Ducted-Electric-Cab-Heater-Air-Cooled-VW-T5-Transporter-Motorhome-/201571715261?hash=item2eee9c48bd:g:Yx4AAOSw3YNXYam3
600w is pretty decent, not in the range of an Eberspacher but should clear a Defender 90 and be...