Actually cancel that - the behaviour of the aircon seems to have changed post upgrade.
Beforehand I could run the tempature at 22C and then hit the snowflake button and it would just come on. Post upgrade I now start the car (Temp left at 22C) and I find that the snowflake button flashes, but the aircon doesn't run. If I then drop the temp down to 16C the aircon comes on by itself - so I gather that the upgrade has changed how the automatic settings work.
I'm not sure if this is normal behaviour, but I'll have a bit more of a play on the way home to see what happens.