for Q1: if the top (what you call roof) is operating fine, you have no issue.
the dash light suppose to indicate the end of the top travel both ways.
so the light will turn on during the travel of the mechanism, and will turn off once it is fully closed, or fully open (to indicate the end of the travel).
the light is controlled by 1 or 2 micro switches (depend on the year).
but before you waste time on troubleshooting, run a simple test.
turn your ignition key on without starting the car, and look at the dash.
if the top light doesn't com up, it might be as simple as burnt bulb.
the reason i'm saying that, is because when the microswitch goes bad, usually the top will not operate properly (depends on which switch is bad)
Q2: your spoiler lights operates as it should. the lights will come on only if the spoiler is stuck in the wrong position. if you wish to confirm its operation (without having someone driving behind you) just place a small piece of clear tape (the one you have on your office desk) and take the car for a spin.
going over 75Mph should cause the spoiler to extract and break the tape.
Edit: i just noticed that you live in london.
so you can just drive 80Mph on oxford street, and look at the shops windows. LOL!