I cut mine down 5 of mine with a mate ,the top is easily sawed as its thin .

Cut the branches first so you can lean a ladder against it .

Cut it in sections top to bottom.

Tie a rope to the top so you can bring it down in the right direction when you saw.

When you have cut down to the bottom your work gets harder due to the thickness at the base ,I bought a £50 chainsaw to attack the base be careful though, still way cheaper than paying a tree cutter.

You can kill the root by drilling holes in it and putting SBK or cover it and it should rot .

Good luck be careful.