I knew a guy that had a hornet's nest right in the upper left corner of his garage door frame. This was when we were in high school. He took automotive spray undercoating and coated the whole nest with it. Then he took carburetor cleaner with the red straw and injected the nest. His old man was furious
Maybee start here: http://www.beesuitscheap.com/
I would get a serious bee suit and modify a pump sprayer by putting a long wand on it made out of copper tubing. Then get the best insecticide you can find and inject it. HAHAHA it's the stragglers that will be hard to get.
Or, blast it with a potato gun
( Or shotgun with birdshot in it)
Or, if you have a bee suit that you are confident with, maybe best to clip the nest out of the bushes and carry it far away.
Great advice eh? Easy for me to brainstorm with no hornets around