Its a petrol (sadly). I was going to convert it to LPG but haven't done it yet. Perhaps a diesel would have been a better starting point.
I did have a Daihatsu charade 1.0 Turbo Diesel a few years ago that I managed 79 mpg out of. Perhaps I should find another and really get to work on it
I'd be happy to answer any questions you'd like to ask. Perhaps by PM or in a new thread (don't want to go too off topic on this thread).