We finally fitted the woodburner, about 1 week before we left for Europe. It is made from 2 gas bottles welded together and I bought it years ago from a man called Geoff in Glastonbury. It used to be in my old caravan, but it will work ok in the van.
We bought single wall flue for the first bit, then twin wall where it goes through the roof so it doesn't get too hot. We also had to buy a bit to convert the single to twin wall, a hat thing/ cowl and a rubber cone thing for the roof to seal ti from the rain. We got it all from the internet. We also got a length of builders band from Wickes (metal strip on a roll for attaching the burner to the floor and walls to stop it from moving) and a granite slab to go underneath to stop the heat (given to us by a friend who makes kitchens).
We sealed the roof with plumber mait putty and silver tape again.