Hmmm... my suggestions... get the battery onto a bigger battery charger - it needs a full charge if it has been operating at 10.8 volts.
A battery should be 12.3-12.6 volts. When the alternator is charging (engine running), voltage at the battery should be 13.8-14.4 volts. 10.8 volts means the battery is seriously discharged and potentially faulty - and no output at all from the alternator. No wonder the car's electronics drop out
at least once the battery and charging is fixed, I don't think you have any widespread 'gremlins'.
The reason the no-charge warning light isn't on, and also the reason that there is no charge, could be that the smaller of the two wires has broken off the alternator. Perhaps the terminal didn't fit due to a difference in alternator models; perhaps it was rigged up insufficiently. The wire serves to 'excite' the alternator windings, allowing the alternator to develop a charge, and it also powers one side of the warning light bulb. Just an idea... but check that wire?
It is possible the warning light bulb itself has blown - seems unlikely, but possible. It should of course come on when you turn on the key.
Never discount the simple causes as I'm sure you know, thank you for reading my posts
I had a Stilo recently - similar belt setup to the Twinspark - and the belt was too long, meaning it was slipping and yet not making a noise due to being a fairly new and supple belt. The length for the Twinspark should be 1975mm if my memory serves, and even a 1980mm might be too long, depending on how well the tensioner is working. So perhaps check the correct length of belt was fitted.
Sorry the suggestions are leaning towards a mistake when fitting the alternator - but as you can appreciate, a new alternator should work for a long time.
It was a new one 11 months ago and not second-hand? If it had been second-hand, then you would have to check the brush length - they do tend to stop working quite suddenly when they reach minimum length.