Sorry Steve still disagree
If you buy a secondhand car how do you know that that privacy and other items were not standard,as you know alot of cars now have this as standard or as a factory fit option.
You would have to have an original car spec list and itemise all non standard items for the Insurance company.
What you are saying is if you change anything on your car that isnt standard your are invalidating your insurance, towbar,bumber protection etc,insurance companies are only interested in performance enhancing,side skirts, rear spoilers aftermarket alloys etc.
Does that mean the door rubbing strips and mud flaps i have added will invalidate my insurance?? as they are changing the appearance of my car !