You would need a large wind turbine to get effective heat from it after your normal usage - I doubt 6kW would be enough.

I considered LPG when I converted this (small) barn, and would probably have gone for it, but I couldn't find a suitable site for the tank. The restrictions are considerable, and much more severe than for oil.

On the whole, I don't regret going for oil, although I was able to use a conventional (rather than condensing) boiler. The cost of a condensing oil boiler 9 years ago was horrendous. Interestingly, the oil/LPG price comparison came down in favour of oil in 1970, 1981 and 2001 - the years when I've installed new systems.

Phil