Rinty,
I have never used the Honda cleaner & polish for anything other than basic cleaning (which I hate doing without a proper bike wash) and giving the bike a light coating of polish/wax. For example it's really good to use while on the road where you might not have access to soap and water.

If your car paint is damaged I think you need to use some special products to get it back into condition. After you've done that you can go back to quick & dirty (no pun intended) methods of cleaning your car, bike, train, etc.

HTH,
tsp
My blog: http://www.swriding.blogspot.com