Why is so much paperwork issued with a speeding offence?

I was recently (January) caught speeding in a temporary speed limit area on a dual carriageway in Essex. Whilst I am not complaining about being caught (I am quite prepared to accept a fine and points)...

What items do I have to keep in my car by law?

Can you tell me what items I have to keep in my car by law please? There two things I can think of which may be required, a warning triangle and two yellow vests but I am not sure.

Does having an airbag light on invalidate my insurance?

Will an airbag fauly warning light on my dashboard invalidate my insurance if stopped by the police in England?

Will my daughter be charged for leaving the scene of an accident?

My daughter was driving home at 3am on Sunday morning in dark rainy conditions, she skidded, lost control and hit the kerb and a traffic light (which was damaged) She left the car in a safe place nearby...