Something you all have forgotten...

That tree was there LONG before the neighbours moved in. If they
didn't like the tree they shouldn't have bought the house. They
definately should not assume that they can do as they please with it!


If they'd bought knowing your garage was built encroaching 2 feet onto their
property, I suppose they wouldn't be able to do anything about it, but would
have to just accept it?

I don't think soooooo!

An illegal encroachment doesn't get to stay there just because they knew about
it when they bought, unless local laws say different.

Now your argument WOULD hold water if you were talking about a pre-existing
problem not covered by private law issues - the classic one being people that
move in next to an airport and then complain about the noise from over-flights.
HELLO - did you buy at night during an airline strike......