You're right to move it further from the building.
But in spite of what the website says, the antenna will definitely perform better if there's an RF ground or counterpoise available at its base. Usually whatever it's mounted to, will help with this, but if you mount its base on a fibreglass pole, it will have only the coax, it could result in RF in the shack, hot fingers when touching your equipment, and interference with the microphone, and even other electronics in the house.
To improve this I recommend:
A counterpoise which could be as simple as three metal cables - one straight down, and two more at modest angles from this, either side of the pipe. Connected to the ground is good, especially if they're very short. You could also run one down the pipe, next to the coax, all the way to your ground stake if you have one. As it's an 80 m antenna, then the wires could be up to 20 metres long, less is probably fine.
Properly grounding the coax as it enters the house, at a common ground that's connected to an earth stake, your mains / shack earth, etc.
If you don't have a ground (second floor shack, etc) then put a common mode choke on the coax as it enters the house. For 40-10 m, if you're using thin coax like RF58, a simple coil of about 10 turns, 6 inches diameter, wound in a single direction would suffice. 80 m requires more. A few turns on an appropriate ferrite would also be fine, search this stack for other questions about baluns and chokes (but it's a deep rabbit hole).