fùair point, something I hadn't appreciated at the time, but I don't think that asking a question about my vehicle in a calm manner could be misunderstood as intimidating. Me taking photos of his van could only be as intimidating as him taking photos of my car.
I'm not going to labour the point as you seem to appreciate that you did overreact... it's none of my business either and I'm far from perfect... However, him taking photos of your car while you weren't there (At first), is very different from you following him and making a point of taking photos.
Incidentally, how far would you have followed him? Would you have done the same thing if he'd pulled up at his house with his family? I'm guessing not.
Anyway, don't beat yourself (Or any van drivers) up about an overreaction! No harm done.