One's for the auto headlights, but the other one is for the dashboard lights. You may notice sometimes that the dash lights are on, but it's not quite dark enough for the headlights to come on? There you go........
No, I have never noticed that happen - I will look out for it.
I can see you all now, driving along with one hand over the sensors . It happens to mine a lot - maybe because it's kept in the garage? Try it out - stand the car, ignition on, in the daylight and cup a hand over the sensors, one by one, to see which lights come on.
Tried my alarm (sorry neighbours!). The horn sounds, as does the alarm. The sensors seem to be in the light housing in the middle of the ceiling.
Locks worked as before - press the 'Lock' on the keyfob once, the vehicle double locks (put my hand through the opened window, and couldn't unlock it manually). I don't think that there is a single lock option.