God this is a ball ache.
From tonight's reading, I have found that to code the new battery to the car you need a battery with a BEM code. Guess who sells them, yep Audi and no one else
So screw that.
This is what I will buy tomorrow once I have verified the dims one last time, its the closest I can find to what's in the car.
https://www.tayna.co.uk/610-200-Vart...92--P3200.html
Apparently if you don't recode the car after a new battery 2 things can happen.
1) Possibly shorter battery life but this is probably just a scare from Audi.
2) The cars electrics may not function correctly until the car has learnt that the battery is strong. As mine died overnight I assume the ECU has a stored a depleted battery status and the only way for the car to learn it has a new battery is by using the car, starting it over and over etc so it learns and begins to reactivate systems that are shut down to preserve battery power.
Wonder if that's why you experienced issues with your new battery Peter?
Cheers