P0420 Jaguar which bank is bank 1

This a common query with "V" engines the ECU has flagged a code that relates to Bank 1.
However which bank is bank 1?
That's easy, it is the bank that contains cylinder number 1.
So in this case which bank has cylinder number 1 is it the right hand or left hand bank.
Without any technical data, this can become a bit of a puzzle but an easy way to find out is remove the coil pack or injector plug from one of the cylinders, this will flag a code relating to the offending cylinder. That way you can identify cylinder 1 and therefore bank 1. In this case the right hand bank looking from the drivers seat.

But what about the code, what is it trying to tell you?
More on that next time.