Airbag and gearbox warnings out of nowhere. Battery again?

[witchy]

Hi folks,

Long time no post for me, nice to see the place is still here. Car these days is a 2016 190GT DSG and I seem to have a lot of battery woes. Had the car since 2019 and all was well up to winter 2021 when the battery failed. Fair enough, it was the original. Got a new AGM stop/start from Halfrauds and was back in business. Winter 2022 it failed again and I got Halfrauds to swap it under warranty. Eventually. What a palaver.

Anyway, last night I headed out in the evil weather to go shopping and got 'AIRBAG!' and 'GEARBOX: ERROR' warnings come up. I've always had 'passenger airbag protection unavailable' since the battery swap.

Car still drives OK, though obviously I'm not planning on hitting anything to test the airbag warning. The DSG is my biggest worry, but this morn I wondered if the battery was starting to go again. Reading here I'm seeing people mention coding the battery to the car; after both battery swaps I've spun the steering full left and right a couple of times to clear 90% of the faults then gone for a drive. Is there another step I've missed?

Cheers!