It used to freak people out, others would flash their headlights at you if you had them on in the daytime. Now all new cars automatically put sidelights on during daytime anyway, I think its a (pretty sensible) EU regulation.
Down-shifting puts extra stress on transmission and engine components which are far harder to replace than brake pads.
If you're heading down a long slope, sure, use the lower gears to add control.
If you're just trying to come down from your amazing commute freeway race into the clover leaf... use the brakes for braking. Most people downshift incorrectly and add unneeded wear to their clutch.
There's few enough sticks out there already... don't leave me one with a beat up clutch.
and normally leave the lights on auto as well.
Why don't you just leave them always on anyway? Or is that not allowed in the UK?