Active job

Brick Chimney removal

I am in the process of removing an open fireplace and gibbing over the gap in our lounge. As we will no longer need the chimney I was thinking if I remove the chimney it will open a big space in the master bedroom that I can convert into a big wardrobe. My job for estimation (and questions) is: How much to remove the chimney from the top of the roof, and patch the roof. Q1: Do I need council approval Q2: Once it is demolished and the roof patch, can I continue to do the rest of the demolition from there on down if it is non structural? Q3: Is it possible to leave the chimney, and support it in the roof, but remove the rest below that behind the wall? Sorry if these are noob questions.