Good news! I got my I-Pace back today after a 5 week stay at the dealer (see the story in the posts above). As I understand it, they've replaced the battery control module with an updated version as well as two auxiliary batteries used for the electronic systems in the car. They also performed the software updates for the H213 regenerative braking recall and the H228 rollup. They left the infotainment at the 18C version until the new SOTA update becomes generally available. I was fine with this given the stories I've seen with newer versions here.
I'll need to take it back in to get a new hood cable they said is going to be replaced on all I-Paces and they're going to attach a new charge label per the H221 service action when it becomes available. They said both of those will be a quick while-I-wait change.
One of the delays on the repair came from them having to wait for a new kit with special protective gear (goggles, gloves, etc.) they must use when doing certain actions on the high voltage systems of the car. They said this was the first time they've (the dealer) have done something like this so it was certainly a learning experience for them. They did say that the TAs in England had seen this a few times before and helped coach them through it while also tracking the work as the repair was done.
Apparently they had to cordon off the area around the car when working on the high voltage steps and at one point had to have two extra people assisting the main mechanic in safety-related roles. I'm sure glad I didn't have to pay for any of this!
It's been so long since I've driven the I-Pace it was almost like driving a new car again and I'm having to rediscover its feel and control differences. It certainly feels a lot better than the loaner Discovery they had provided.