Dont go for LPG as your running costs will be far more than oil. Have a look at http://www.oftec.org/news_and_press_releases/latest-fuel-prices-show-the-gap-between-oil-and-gas-is-shrinking
and also http://www.oftec.org/news_and_press_releases/calor-gas-ordered-to-withdraw-misleading-advertising
What age is your tank? We recommend that your tank is dipped with a water finding paste to see if any water has settled in the bottom and remove any water if you find any present.
All tank outlets are usually about 1" up from the base to allow settlement to settle below the outlet and...
Oil is your cheapest option - Have a look at this http://www.oftec.org/news_and_press_releases/latest-fuel-prices-show-the-gap-between-oil-and-gas-is-shrinking
Always shop around when you want to order your fuel and ring 3 or 4 different companies to compare costs - try the independent...
Its its not possible for you to get your tank 760mm away you can either fire protect the boundary wall or install a ready fire protected tank. This is the best on we have found available on the market...