Fuel Oil is fine for the BSS and I quote,
2.1.2 Is the fuel in use correctly and clearly marked on or adjacent to the fuel filling point? R Check for markings on or adjacent to fuel filling points. The specific fuel type in use must be correctly and clearly marked on or adjacent to all fuel filling points: • ‘Diesel’, ‘Fuel Oil’, ‘Gas Oil’, ‘DERV’, or ‘Biodiesel’; or, • ‘Petrol’, or ‘Gasoline’; or, • ‘LPG Butane/Propane’ as appropriate; or, • ‘Paraffin’ or ‘Kerosene’; or, • ‘Petroi.