Is the Road Traffic Act volume not a restriction on fuel for the vehicle? The 200 l mentioned in the CAA Mogas booklet "must be for your own use. You cannot ask an employee to carry it".
Maybe chainsaw and grasscutter guys know current the situation. I've certainly seen guys filling a drum in a landrover at a filling station. (Not in a city)
Our airfield provides flamable liquid storage cabinets for any fuel for refilling after the flight. They take 2 X 20 l cans each. And I fill up on the way to the airport.