Well, after 2 hours on the cheapest old 4Amp iron core charger

I reconnected the Battery just to move the car
Vehicle started, all faults gone from the instrument cluster apart from the yellow DSC.
A quick left to right on the steering wheel and that cleared.

After stopping the vehicle, the battery was up to 12.4v

So it would seem, all of this is due to a discharged/underchagred battery


Next move is find out why??

Alternator?
Parasitic Drain?

Another question, is there any difference in leaving your key in the ignition, doors unlocked.
Or removing the key and locking the vehicle in relation to power drain for over night storage?