From long distant memory, which aligns with some photos I happen to have of a catalogue of Lucas rotary switches of the period, the wiper motor switch and the panel light rheostat also utilise spring loaded pins. From more recent memory the selectaride switch (did the 409 have selectaride) used a screw fixing.
Have plenty of labels handy if you have to disconnect any wires, the wiper motor switch is a particular nightmare if any get ever confused.
While you are at it, if you ever want to see the instruments in the dark, may I recommend changing the instrument lighting bulbs for LEDs. I found that if one leaves the filament bulbs in the lighting above the heater controls and other switches their current drain is sufficient to allow the original panel light rheostat to dim the instrument light LEDs, whereas if you change all to LEDs it probably won't and you'll also have to change the rheostat to retain dimming.
Changing the interior light to an LED is also much recommended.
Roger
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