Hi James:
I have a Toaf which I use for my two Rover 75's. However, I have checked and there are nearly 400 miles between you and me as I live in Segovia.
For your draining problem, I have a Rover with a sunroof and I could help you to unclog them.
For the Airbag Light, in most cases the problem is corrected by disconnecting, cleaning, and reconnecting the plug under the front seats. You would have to test which side is generating the signal.
The side impacts. How do you come to the conclusion that you have problems with these? If any are to be located it would be at a junkyard.
Let me know if I can help you.
Kind regards.
Joel Antonio.