This is the last 24 hours, a three degree drop doesn't look too bad (no heating on) but it certainly feels very chilly.
Not surprised it feels chilly, its getting down to 18C, you need to do something about that
This is going back as far as possible with lowest magnification - last 30 days history. Yellow line is the room temperature, lumpy green line is outside temperature, and other green line is the thermostat set point. Looks like it is at the point where heating would cut in, except boiler is turned off. Basically in all that time, even though external temperature has gone down to 5C-ish on a few nights, the room temperature hasn't changed. On days when the sun has been strong there will have been some solar gain, which building will have absorbed and hung onto for cooler days (thermal mass of internal walls is deliberately high).
I'm not doing anything clever here, this is exactly what the building is intended and designed to do
Basically in the middle of the last 30 days the temperature climbed 1C, and now it has fallen back again (lousy weather recently), and throughout it has oscillated 1C most days.
the whole feeding the grid vs self consumption element is the trickiest bit.
Most people must be out-to-work Mon-Fri and unable to take advantage of the PV, exporting it, and getting "presumed 50% export" payment. I too have the presumed 50% export payment FIT, but I don't think I have ever actually exported a single kWh ...
If you've got plenty of roof
I would hazard that:
South first, West second because it peaks later, overlapping when folk come home from work / cook evening meal (for those may even be better than South) and East last (generates early, most probably when even at-home people are using very little power).
North = better have good FIT kickback!
I have high efficiency Panasonic panels
I bought Panasonic panels (more than 5 years ago) because a) all-black looked better, and b) they are warranted to lose what seems like only a tiny amount of generating ability over 20 years.