I personally would inquire as to who the plot holder is , and I would cut down anything on my side. But if the man is sick or can't get down there maybe he would be glad for someone to cut it down.
On our plot i have a crossed fence so you can see through it, but was told it was to high. So i have said i will replace it when the person who owns the plot next to me takes some time to tidy it up , as i don't want to see his rubbish and way overgrown weeds. When i explained this I was told 'Fair Enough'
It makes me mad that people are crying out for plots and you get people who have one and don't give a poop >:(