Noone has a right to a view under planning permission laws. The fact that they have to look at your extension from their gardens should be of no consequence. They can object if you are going to obstruct their light, but even this does not always stop planning permision being granted. So, unlesss their are any local bylaws, I would not worry too much at the moment. You sound as if you have a crabby lot of neighbours, especially as they have all got their extensions. Good luck to you.