Looking for the location of the coolant temperature sensor on this car.please advise.
This thread shows the coolant level and temperature sensors.
https://www.jaguarforums.com/forum/xj-xj8-xjr-x308-27/engine-coolant-thermometer-sensor-70566/
Also, though 
https://parts.jaguarlandroverclassic.com/aj810031-temperature-sensor.html