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.
I’ll post pics/video once I get it running, too.