In reply to Hooo:
I put a reconditioned external vented gas heater powered off a safefill , about £550 all in, last winter in my van conversion.
Need the gas for the hob anyway and cheap to run.
A traditional 6kg , about 12 litres gas , steel cylinder refill cost me £34 recently. Autogas lpg is about 90p litre so I can get the same amount of gas (propane) for about £11.
Safefill do 5, 7.5 and 10kg versions, other brands available. Also good about the safefill is its translucent composite stuff, so very light and you can see how much is in it.
So light that the first time you pick up one up you need convincing theres any gas in!
Post edited at 20:55