External temp sensor & wing mirror glass questions

Still loving my S-Type.  Just had the first big (ish) bill though.  Both lower spenny arms on the front needed to be replaced + new pads on the front.  I was getting a bit of a 'graunching' noise from the front just as the car came to a stop under braking.  Was obviously knackered joints on the arms making the noise.  The car was also feeling a little unsteady in it's handling.  All good now though.  No noise and rock steady handling once again.  Bill came in at over £600 though and that was with after market parts.  Ho hum....

That aside, I have an odd, intermittent feature with the external temp reading.  Usually when I get in the car to go home from work and it's clearly latter teens in temp outside, I turn the ignition on and the external temp will be reading much lower.  If I switch ignition off and on again, it sorts itself out.   Is this common?  Wondering if the sensor is a bit flaky but no clue where it is located?

Finally, does the wing mirror glass pop out if pulled, without having to completely dismantle the unit?  I know some wing mirror glass on electric mirrors kind of has a ball joint on the back with matching female socket on the unit which it pushes into.  Not sure if that is the case with these?  Been hunting online for some images but not come across anything yet.