Audi A3 2.0 TDI Low battery warning

[Bodgedbuild]

The mother-in-law has an issue with her Audi A3, it is a 2.0 tdi, BKD, 2006 MY engine same as MK5 Golf and it displayed a warning for low battery on the graphic display along with ABS/Traction control/Steering warning/engine management lights on the dash.
I checked charging at the battery, 14.2 volts, I also checked the battery condition sight glass and it shows a green ball.
I check both sides of the maxi-fuses in the under bonnet fuse box, again 14.2 volts and the "buzz bar" with the strip fuses mounted on the front of the under bonnet fuse box, all 14.2 volts and all measured both sides of the fuse.
I am currently unable to find my VCDS lead but I suspect it will show a bunch of ABS/steering faults.
Could anybody suggest any common problems given that the car starts and drives normally apart from the warnings? Obviously I need to rectify before the MOT.

 

[johnny2007]

Had a similar problem with a passat, so take it with a pinch of salt.
It was a abs sensor on one of the wheels giving a false reading.

 

[Bodgedbuild]

Had a similar problem with a passat, so take it with a pinch of salt.
It was a abs sensor on one of the wheels giving a false reading.

I'd understand if it was just ABS/steering but the MFD is showing a big animated picture of a battery with "battery low" (which it clearly isn't) can't help but wonder if the alternator is knackered but still charging?

 

[Burnerman]

Can you check the battery voltage once it has stood overnight - and again when it's cranking?
Had exactly this on a 13 plate Freelander and although the car never struggled to start, a new battery sorted it (The battery was the original one.)
John

 

[Bodgedbuild]

Can you check the battery voltage once it has stood overnight - and again when it's cranking?
Had exactly this on a 13 plate Freelander and although the car never struggled to start, a new battery sorted it (The battery was the original one.)
John

I'll give that a go, I thought the little green ball in the sight glass meant it was fully charged/good but I guess that is just a hydrometrer rather than an actual indication of battery fitness.