Diesel fuel "Waxing" is a well known problem with road vehicles in low temperatures. Normally the fuel suppliers provide "summer" & "winter" grades, to help reduce the effects. Fuel tank heaters and insulated fuel lines are often used in cold climates. When the engine is running the fuel from the injector "spill back" lines is usually warm enough to keep the tank temperature up. I know JET A1 is very similar to road diesel, but quite what Theilert have done to get round this I'm afraid I don't know.