After a lot of going backwards and forwards with JLR I was finally able to update my maps today.
The original issue was that I could add a vehicle to my jaguar.here.com account but it would not stick. As soon as I confirmed the VIN and the system told me that I had an qualifying vehicle but then poof, like a rabbit in a magicians hat it was gone.
Yesterday, I found that my VIN was there in the account!!!
I downloaded all 700+ bits of the UK, Europe maps to a suitable SD Card that was plugged into my Mac. That Card went into a USB holder and bingo I was able to do the last part and update the car.
Now for OTA updates!
Faults and Technical chat for the Jaguar I-Pace