I also saw stuff on the web about the legal action over excessive parasitic drain on some Subaru models, but as far as I could work out these did not include any Levorg models - but I might have missed something.
I've since bought a clamp-on ammeter (Kaiweets HT206D) to try to work out what the battery drain is under various circumstances. Immediately after turning the ignition off there's a drain of up to 1.5 Amps, but this slowly decreases over the next few minutes. The local Subaru dealer suggested waiting for at least 10 minutes for things do die down - what on earth is drawing so much current for the 10 mins after you stop driving and lock the car I can't imagine, but there it is. The clamp-on ammeter is not very sensitive to small DC currents as it has to measure their magnetic effect and there can be other fields about that make this difficult, but my meter can just about measure down to 10 mA. My observation is that after a few minutes the drain does indeed reduce to something like 50 or 60 mA. That is what the garage also measured and thought was reasonable.
To me that's still rather worrying. Suppose you leave your car in an airport car park for two weeks, 60 mA x 14 days x 24 hours makes 20 AH - so a 60 AH battery would be one third drained by then. If it wasn't fully charged to start with, or had lost a bit of capacity over the years, then you might well have a problem restarting the car. That seems a very poor design.
The other bit of really bad design, which I think may have caused my battery to get flat in a few days, is that the "dome" light which one uses a night to see things on the rear seats or their footwell can be switched on in two ways: the slider switch turns them on when a door is open but they go dim then off when the last door is closed; but if you press the lamp housing it turns it on in exactly the same way but then it says on indefinitely as there is no auto-off in this case. Since these are filament lamps (which is stupid when LEDs are so much better for the purpose) of about 8 Watts they use about 667 mA, so just leaving one of these lamps on for a couple of days will easily flatten a battery. I think one of us probably needed a light in the back just before leaving the car, but with smoked glass windows (another design nasty) you can't see that they don't go off after the door is closed, and this may be what caused our battery problem. By the time I found out the battery was down to 8 volts and probably damaged. We live and learn. I've removed these filament lamps from the housing so this will not happen again.