Thanks for the write up.
However, the people using the Free 3 data sims on the XE forums seem to miss out one or two of your steps without any issues.
They get the sim, go online and register it and then put it in the car.
Thread from 2018 when they came out and nobody found the need to do other than plug it in once registered:
Free data sim - Jaguar XE Forums
As it's a data only sim and registered now it activates using the auto select being on so it recognises the 3 network and just auto connects to it as the paid for versions.
Can you explain the difference and why you can't run it on the normal 3 network (default) and why you need to create a new register of "3internet".
Just wondering what the difference is ?