Right, all seems to have gone well. She is on charge at home and we will see but the signs are good, taken 30 minutes so far which is far more than she was doing (failing within 5 minutes consistently).
The garage said CCU replacement went well, they have also done a bunch of module updates to improve various things including ACC, LKA, SOS phone (all things I mentioned).
They were almost astonished that it had been so smooth, which says a lot about the normal update experience!
And we've been put on R46, which I think is to try to sort out a problem with the app whereby it won't preheat the cabin at all under any circumstances.
Will try to give her a 100% balance tonight and test various things out in the morning.