Ash die back is root rot by another name , I removed one I could not believe how soggy mushy and rotten the roots were,The trunk was rotten half a meter over ground,
If you leave it too long to remove it will just fall over in time,once the roots fully rot,
If you are going to ask the council to remove it no harm in saying you have been staring at it a bit longer than you have and say it is ready to fall over,
the one I removed there was no need to remove roots as they were already rotten,
I sowed a Copper beach in its place and I had to fill the cavity left by the rotten roots before planting,
During the last storm an large ash tree fell that looked very healthy when it fell you could see it just gave away just below the soil some of the roots are attached still I see there is buds coming on the branches,
Yet when you look at where it came away from the ground you can see some of the rotten roots from ash die back,
The point I am making is seeing it is a small tree and dead a few years more than likely the roots are fully rotten by the time the buds stop appearing for want of a better word,