Hi Malcolm,
the receiver/sender unit for the tyre sensor is behind the dashboard on the N/S (on my car at any rate!) and the power cable can be easily unplugged - once you get to it!
It may be easier to go straight to the sensor readout panel.This is accessed by carefully levering out the leather armrest pad from the rear which should then reveal a couple of cross head screws securing the plastic/turned metal armrest to the tunnel.Once these are released you can lift up the complete armrest unit.A couple of tiny screws in the black plastic cover gives access to the rear of the sensor display.
I have often thought the cut out could house some other display;not sure what !
Hope that helps, James