Cleaning seven storey work was a pain in the backside trying to pick the ideal day with no wind about, but at that height there is still a breeze even on the calmest days. Too strenuous and dangerous for my liking working at that height. I don't mind do 50ft every month but no higher.
It's impractical to clean at that Guiness record even if someone was above guiding the brush head as it doesn't exert enough pressure and to put a heavy 45 brush on is ludricous.