Thank you for all your helpful suggestions, it is such a shame when your life is made miserable by a selfish neighbour.
Hetty can I please comment on two points you made.
I am quite aware that tree pollen is is the air, it is the job of clearing up the constant mess that I object to.
The other point that people are allowed to do what they want in their own garden yes, up to a point. This person planted trees on the borders both sides of his garden. One tree spreads out over 4 gardens. The others all fighting for space have all ended up completely over mine and the neighbour the other side. Preventing us from having the garden we want, he planted Leylandi to divide from his neighbours at the front of the property. The neighbours had to have lights on permanently as it was so dark. They grew higher than the house. They took the telephone lines down, he was presented with a huge bill, he denied having ever planting the trees, the neighbours were asked, they said they were his and he had refused to cut them down. He denied all of it. In the end the trees were cut down completely whilst he was on one of his two month holiday breaks. He did not foot the bill. He is a thoroughly unpleasant person. He speaks to no one and this is a friendly road, that is why I have stayed here so long. All anyone expects is a little consideration an to be a good neighbour, we all need to get along.
I love seeing different gardens and what people do with them. He had a solicitors letter to the house next door as he didn’t like a tree they planted. It came to nothing.