You need to employ your own assesor. They normally take around 10% of the claim as payment but they normally get you 20% more anyway!!
I told my insurers that my legacy had a rear spoiler (a genuine subaru part) and they withdrew cover! Its a joke. Eventually they agreed to reinstate it but they said that the spoiler wasnt covered!!! i also put after market alloys on it and again they refused to cover the wheels. So be warned lads, ANY changes, you need to notify the insurers.