Today I received information from our central heating oil supplier about the Fuel Box:

http://fuelbox.co.uk/

UN approved 20 Litre bag in box system.

Suitable for all off-road diesel engines, fitted with DPF, EGR and SCR systems including modern machines calibrated to EN590.

• A fast efficient, easy to handle, refuelling solution.
• Glug free pouring system prevents unnecessary spillages.
• Zero risk of contamination.
• Reduce downtime by storing onboard your vehicle in case of emergencies / runouts onsite.

A unique specially formulated Additive System, achieving an outstanding performance over conventional Red Diesel/Gas Oil.

• Improved cetane rating (boosts power).
• Improves combustion efficiency.
• Improves fuel consumption.
• Reduced visible emissions (smoke).
• Protects against wear in fuel pumps / injectors.
• Enhances the performance by up to 15% of older engines.
• Disperses existing sludge build-up.
• Contains demulsifiers to combat water build-up.
• Reduces deposit and varnish build-up.
• Improves storage stability (By up-to 2 years)

Help lower your carbon footprint and meet your sustainability goals. After use this product reduces packaging waste in landfills by 86% and reduces plastic consumption by up to 90%, compared to 20-litre rigid packaging. – The FuelBox

It seems that it is like a wine box but for 20 litres of diesel.  It does mention "marine applications" and it does give some food for thought ... 

However, still stow a wine box or two but just don't get them mixed up.