My neighbour’s roof terrace invades my privacy. What can I do?

Our next-door neighbour installed patio doors from an upstairs bedroom leading onto their kitchen extension roof. The roof has now been made safe with an iron railing around the three sides. They began using it rarely as their terrace for drinking/entertainment. When they are on it they directly look into our garden over the 6ft fence, which we own.

Alas, the widowed owner now has to go into care and the family has put it up for sale. What can we do legally to regain our privacy in our own garden? I worry that it might be used even more often if sold to a large family.Overlooked neighbour

Your first port of call should be to check whether planning permission was obtained for the