I took the opportunity to take the pictures while I had the mirror glass off to refix the cover that had popped off after being clipped by a passing car.
Really just to show how the retaining spring/wire sits. Also shows the clip that retains the wire ends. These have to be released from the hooks to get the glass off.
Mirror clips to the round ring face of the motor. Note glass heater wires disconnected:
The retaining spring:
Retaining spring in place ready to clip back on. Note that the upper wire is close to the heater connector which gets in the way of releasing it:
I use the suction foot of my Tomtom satnav to hold the glass while taking it off and putting it on. If you press on the edges of the mirror, it will break.
Back in place with a firm push and the suction foot removed: