What about one of these? RFL is free, also runs on ponds (drinks them!) and a bit of scrap wood and coal. British made !!

Mind you, my annual Boiler Certificate ain't cheap... nor insurance come to think of it

http://flic.kr/p/c36hQQ

(Can someone clever get this photo to post - I tried 3 ways then gave up)

Stuart
"There's no skill substitute like cubic inches."