Given them up, too much hassle from the downstairs occupants especially when the front garden belongs to the top flat and the back garden to the bottom flat.
Even though we never trampled plants or damaged the other gardens so many people are territorial about their gardens!
One downstairs flat had grey paint splattered all over the windows and they still insisted it was the water from above!
Tried the "Well, what happens when it rains it's just the same isn't it?"
Reply "Well it's not raining is it?"
Simpler just to avoid unless you really need the work.
Or make sure you clean them when it's P*****ng down then it really is raining isn't it!