Ideally your fuel tank will be located in an accessible and safe location where any spilt diesel will not be a major concern. (Because let’s face it – sometimes we dribble a bit here and there).
Alternatively – if you don’t want to permanently mount your tank you can use a ‘quick disconnect’ fitting to allow you to remove the fuel tank for refilling.
The one pictured is usable out of sunlight as it is not UV stable. However if you want to use in the outdoors then a metal fitting will do the job.
The beauty of these fittings is there ‘non-return’ valves on either end meaning no more diesel spillage.