Hi Geoff
I have a trickle charger as well, just hadn't put it on for a while. Have now set up a diary reminder on the phone to charge once a month. Have noticed quite a lot of people in our area having to use jump leads as their cars have been left idle for so long.
As for tyre pressure, is the setting not in the normal menu, you should be able to accept the tyres as they currently are. I get this when I have put the winter wheels on / swapped again for summer. The warning comes on as the winters are 215 not 205's so trips the warning.
Andy