The tow bar harness plug is under the LH side boot trim, which is where the towing module is situated.
PDC is a multi vehicle term for Parking Distance Control (reverse sensors).
CJB is the main body module, often referred to as a BCM (Body control Module) in other vehicles.
The CJB needs JLR SDD, or other diagnostic equipment to program it to add towing capability.
You don't need to have the CJB programmed, but the PDC will give you a warning that something is behind the vehicle, whenever reverse is selected and the trailer is attached, which can be annoying.
