I live in a semi-detached, my neiughbours have built a conservotry , 3 meters by 7 meters ,it is approx 7 inches away from my kitchen window, is this not depriving me of my privacy. Also they have removed the stench pipe from the back of there house and blocked it off can they do that ?

Where are you located? What country?

In most areas the local building codes will end this problem by making the opposing party meet the codes.

It doesn't sound like they can, most codes keep you away at least 15ft