I made this one, then when visitors to my workshop noticed it they wanted one. So I've made a few of them now. I used a taller gas bottle for my workshop as it's easy to chuck a 2' offcut length straight in the top. The small ones work just as well but need more feeding. When its really cold i get mine going with wood then I chuck some coal in too and it stays hot for hours.
This pic is outside when I test fire them to burn off the paint. It's then used inside and the collar simply pushes into the base of the 125mm Stainless flue liner I salvaged for a chimney installer.