You're well over the 90 day mark where E10 is well into its degradation and standard unleaded is starting to sour. A nice problem to have in many respects, but just to be aware!

I drive a Mitsubishi PHEV. And it enforces this by not letting you drive on battery until you fill at least 20L of new fuel. So you're forced to use a portion of the tank at least every 90 days.

I appreciate the warning, will certainly do some homework here.

Apparently petrol here is almost never mixed with ethanol so at least I don’t have that to worry about.

I’ve already topped out the tank with 95 (as it apparently has a better shelf life than 93) and will be driving in HEV mode until it’s nearly empty, thereafter I plan on generally only filling up with 10l at a time unless I’m going to be doing a long distance trip.