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We have canisters which are this size http://www.wheresmymammoth.com/projects/properfurnace/img/1.jpg
Although I'm pretty sure you can get them in various sized. I've seen ones half that size when collecting my new bottles. Im pretty sure they would legally have to be kept outside though. I wouldn't want to risk having them inside my house anyway.
I had it installed by a local Independent gas fitter. This was about 5 years ago.
thats a 47kg