It appears that the Fuel Tank needs to be removed to replace the Fuel Tank Pressure Sensor.
Here is the JPEG file I created from the JTIS software's on this sensor removal/install (click on the image when the webpage opens to get a sharper view):
I also included a number of photos I found on the internet showing the sensor part number and where it is located.
The only price I could find for this part was on gaudin jaguar parts.com - List price $141 discount down to $114.
Found a used one on Ebay for $74.