Also, getting the "tree officer" out shouldn't cost you anything.
Even if you're in a conservation area, you'll be fine to cut it down if it has a fungus. I'd be careful though, although know nothing about it - can you safely dispose of / saw through a fungus infested tree????
In general though, I'd think carefully before getting the tree officer out for every whim. I live in a conservation area. Our neighbours wanted to check that they could cut a tree down. Tree officer came out.....
It turned out that the tree they wanted to get rid of wasn't listed on their register. So the tree officer added it, and then told them they couldn't cut it down!!! Doh!!