Do you have access to forscan?
If not, I'm only in Derby I'm happy to plug it in and take a look for you
I've driven the car about 1500 miles since the battery light came on in Scotland. As I said before, the batter is 12.4V and when the engine is running with all the accessories on the alternator is providing 13V.
You were right on the money when you asked if I had Forscan. I got an adaptor off of Amazon and Forscan returned several fault codes related to the generator, for example, open circuit and ground fault. I am booked into a garage on Wednesday but would love to fix it myself if anybody has further ideas. Just one more thing to add: in the frosty weather I noticed that the front screen heater was not working. I pulled the two 40A fuses, which were not blown, but the battery light remained on.
I've attached a text document with the Forscan report.