My house adjoins a small river in which trees are frowing, rooted in the water, on the far side from my garden. Over the years, these trees have grown to several times the height they were when I moved in, destroying the view I originally had over the distant hills. I found out that the trees are the responsibility of the landowner across the river as a result of riparian rights (to the middle of the river). Myself and my next door neighbour negotiated with the woman property owner to have the trees cut back. We had to pay, though, as she said she couldn't afford to, so I suggest that your nighbour is more likely to agree if you offer to go halves or even stand the cost yourself, since it's you who wants the tree pruning.
I've got another 'keen'... Ouch!
Angela Rayner lashes out and calls Sunak “pint sized loser”.