Churchill do not cover tree root damage to drains

We contacted Churchill over Christmas as we had a blockage in the soakaway to our septic tank. We had a similar problem a number of years ago and it cost £2300 to fix as we had to have part of our soakaway fixed due to the tree root damage. This was all covered by our buildings insurance. When I spoke to Churchill they said that I wasn’t covered for this because I didn’t take out ‘accidental cover’ with them. How tree roots can be described as accidental I do not know. It is a force of nature. Every drainage expert I spoke to couldn’t believe this wasn’t covered under our buildings insurance. As it happened, the roots could be flushed out for £99 so it wasn’t a problem. What is the point though of having buildings insurance if you can’t claim for things like this? I would NEVER use Churchill again. What else do Churchill put under the banner of ‘accidental damage’ to get out of paying for basic things that relate to your buildings