Just switched to gas so am geting rid of the oil tank which has almost a full tank of oil. Would anyone buy this off me? and if so who? Cost me �400 to fill it up
Selling it back to the supplier is not going to produce much of a return for you - he's got to come out, pump it out, take it back to the yard, check it isn't contaminated (he can't sell it to anyone else otherwise).
Better to try and find a near neighbour with oil to take it off your hands for say 20% off the market price.