This time the spare was down 0.1 bar, so I dug out the compressor and boosted it back up to the crazy high 4.2 bar it should be at. The spare does seem to slowly lose pressure with time (when I got the car it only had maybe 3 bar in it), though that's not too surprising given how high the air pressure is in it. While I was at it I also topped up both fronts by 0.5 bar as well. Still plenty of tread on the tyres (6mm or thereabouts).
Oil is at around 4/5ths which I decided wasn't worth trying to top up. This is about where it was last month, despite doing significantly more driving - 560.6 miles, to be precise (over twice my mileage for April - and yes, I did reset the trip counter so this isn't cumulative!). Alfa oil consumption is weird.