"KThose two trees are acer campestre - field maples and they looked self
seeded to me. If you want evergreen, so that you have privacy in
winter too, you could either plant a holy or holm oak - it's not rapid
growth, but how long do you have and how much can you afford? A friend
in a similar situation as you planted an hazel contorta, its twisted
branches are wonderful in winter and obscure the building across her
garden quite well, it is also interesting in spring with its yellow
catkins. After about 10 years it looks splendid.

It's never going to grow tall, though.

--
Kay

How tall does it have to be, I have several hazel contorta and they are
about 16ft tall + and fill out a lot if space but perhaps not tall enough

kate