Solved - it was the CoC, on the German checker site -
https://www.bmw.at/de/footer/quick-l...-aktionen.html - my car showed green, 'no outstanding recalls or technical issues' (translation).
I had the same stop code and the same improvement code so on the face of it you'll have the same outcome as me...
Car is booked in for Monday, 3pm pickup!
Still don't think BMW handled this well, but good result, eventually.