My neighbour kindly informed me today that they would like to build over their garage to extend their house over the second floor. At the moment they are in the "thinking about it" stage and have not submitted any plans etc, but i wanted to know where i stand with regard to how close he can build to our windows. He is a diagram of our layout:
My question is - how close can he build to my house, considering i have two windows that would be completely blocked if he built over the entire top of his garage?
I'm not trying to be a pain as they are nice people, but i really don't want to have a brick wall when i open my window and no light coming in either the up or downstairs windows? Also, most of the houses on our estate are like this and nobody else has built over their garage like this in the 40 odd years the estate has existed as it would not even leave a metre between houses?
Any help much appreciated...

My question is - how close can he build to my house, considering i have two windows that would be completely blocked if he built over the entire top of his garage?
I'm not trying to be a pain as they are nice people, but i really don't want to have a brick wall when i open my window and no light coming in either the up or downstairs windows? Also, most of the houses on our estate are like this and nobody else has built over their garage like this in the 40 odd years the estate has existed as it would not even leave a metre between houses?
Any help much appreciated...