Fuel (Petrol) waxes as it gets old/stale and clogs up the injectors.
January to July is a long time, if you are going to keep with your current driving style, you may be better off only adding ¼(0.25) of a tank at a time. That way you would be diluting to old with new - and you may get a better range by carrying less weight as 20 litres of petrol weighs 14.7 kg
Fuel for sale. A bit old, but cheap. 
Just a small update: It turned out that AI was hallucinating when stating that the 300 versions have a built-in 7.2 kw board charger. It’s an optional extra in the Netherlands, so i’m stuck with 3.6 kw. For home charging it’s not a real issue, but for public charging it’s not really ideal as I take up the spot for at least 4 hours (and some start to charge money for holding the charger after 240 minutes).