I believe it was a type of Ash Tree, photo 3 is the best photo I can find of it at the moment before it got cut down.

I received a letter about it being trimmed attached to my doorstep but that was the only notification I received. It is above 12" in diameter at 4 feet tall which might be the legal requirement (e.g. protected status) for this type of tree in my area (need to double-check this).

I'm absolutely shocked, this is not pruning, this completely killed the two trees in my backyard and without permits from the city.