wow, I worked in the oil distribution business for 12 years and don’t recall there ever being domestic heating oil rationing.
Mike, I’m afraid TooTall is right, first question is whether your heating boiler runs on kerosene (also known as standard burning oil SBO, regular burning oil RBO) or whether it runs on Gas Oil?. Most oil fired boilers run on Kerosene. In the slim possibility it runs on gas oil, then some rural petrol stations have gas oil on pump for farmers and the like or you can stick some Diesel in if you get seriously desperate (exactly the same stuff as gas oil, just with duty added, so loads more expensive).
Kerosene, you almost certainly won’t be able to get drums filled, the only chance you might have, if you have your own drums, will be at a small fuel depot with it’s own storage tanks ie not a major terminal (alot of distributors operate out of an office at a major terminal). For example, if you live within say 30 miles of Birmingham, there is a very high probibility that all the fuel comes from a massive terminal in the centre of Birmingham and there is no way you would even get past the front gates let alone be allowed to fill your drums.
Your best chance might be with the smaller independants who might have a small satallite depot near you. But even then, there is little probability they will have the facilities to do what you are suggesting, but worth phoning round and asking.
I think this question came up last winter and there was talk about possibly buying drums of Kerosene from large farm shops/retailers, so might be worth a couple of phone calls round large farm suppliers, but again I think it will be a dead end.
