Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:2140853.
After struggling to top up the screen wash in my car without it going all over the place, I decided that it called for a bespoke funnel to make the task easier. It is designed around a 2014 Audi A7 which has the screen wash bottle right next to one of the bonnet hinges making it awkward to pour from a 5 litre container. The spout fits neatly into the filler neck of the bottle whilst the incorporated stand helps to steady the funnel leaving both hands free for pouring. First world problems and all that, but hey, I've got a 3D printer so why not.
Version 2 - Although my original design seemed to work quite well, and judging by the amount of downloads it's had it's also helped others too, but there was one small design tweak that I felt was needed to optimise the design. I've now added a small vent to allow the air to escape as the washer bottle is filled with screenwash. I haven't tried it yet, but I've no reason to think that it wouldn't work.