Insurance companies in the UK should be shot, hung and quartered.
I do miss the days abroad where a car is insured for a certain value, that is it. Anyone can drive it, anything can be modified to it.
If you want to drive "safe" here on winter tyres, how would you do that? Notify the insurance company that you are not on run flats anymore as they are winter tyres and that means you have modified the car and no longer insured? In certain European countries it is a requirement to drive on winter tyres as they are safer. Oh no, not in the UK - you would invalidate your insurance. Useless money grabbing lot.