Finally got the rocket stove working, seems there is a trick to getting them to light – the main chimney needs to be warm to draw air in through the side, so I put some burning newspaper in there, and that did the trick.
Not sure if I should cut the chimney down a little, bring the saucepan closer to the flame. I’ll see if I can find my hacksaw.
Here is the result of my project: a mini Rocket-stove, assembled out of old chick pea tins and vermiculite (the vermiculite is the insulation around the sides).
Rocket Stoves are very efficient at burning stuff, and I intend to take this camping at the weekend and cook my meals using only a few twigs. I haven’t tested it yet, as my yard is quite small and shared weith my neighbours, not sure they’d appreciate the flames.