Shaun, alot would be right. The insurance companys spend more time trying to get out of paying rather than settling.
I stopped mine a while back when i heard about the cleaner that changed the colour of a suite he was working on, it sounded like an indicator dye problem ( which is down to the fabric manufacturer not using the correct dyes or the dyes not being stabalised correctly) but because the cleaner had not spent an hour on testing the suite with his chemicals and fully drying it out to ensure no shrinkage or dye problems , they refused to pay out.
For high risk insurance on things you are working on you need to do a full test on audit and put it down on paper, this should be done in front of the customer as proof with a signature at the end, then they may pay you out if your lucky...