I would ask an insurance agent. Probably cheaper than a lawyer and any issues would be battled out between insurance companies anyway, not between your lawyer and theirs.
You could also ask my wife’s sister. One of her neighbors did something (I want to say – cut the roots of a tree that was on the neighbor’s property, though I don’t know if they were causing damage) that caused one of her trees on her property to start listing to one side, creating a hazard.
The insurance companies decided to rip the tree down and compensate my wife’s sister. Her neighbor’s insurance company paid to take out the tree AND wrote her a check for over $20,000, which was the appraised value of the very old and glorious tree.
So, I’m not so sure you can just chop those roots. Again – if it were your land, I would recommend that you with your insurance company. Maybe even file a claim and see where it takes you.