P2098 update

What kind of diagnostic tester do you have? What's it showing the P2098 code is?

Post catalytic converter fuel trim system too lean bank 2.

So, the O2 after the passenger's side catalytic converter is reading too lean for the computer's liking. My guess for the reason it illuminates the SES light immediately upon restart is probably because your long term fuel trims are drifting all the way to lean values. When you start your LR3, the initial checks pick up on that and on goes the light.

Resetting the light doesn't bring trims back to "normal" values, so adaptations would need to be reset to get it to stay out. That is assuming the reason for the lean signal to persist has been remedied. Perhaps the O2 is faulty? They typically fail lean.

Do you have an OBD2 scanner? Maybe check the O2 sensor voltage while the truck is running. If the numbers stay near or at zero for bank 2, sensor 2, you probably found your problem. If that fixes it, you will have to drive a bit to get the adaptations to reach normalcy or you can pay your friendly neighborhood Land Rover shop to reset the adaptations.

Good luck.