Just moved into a brand new home (UK), and have a 6ft wooden panelled parameter fence around our garden. The house backing onto our back garden have this day constructed a 10ft metal Gazebo which backs onto our 6ft fence, its obviously clearly visible to us, and we don't like it. Could there be anything we can do to oppose this. Well, I've your answer. I don't know if I should answer for the UK – I only have experience in the US, where it depends where you live and what kind of local controls there are on such structures. Building codes and zoning regulations might apply. Check with your municipality to view if they should have gotten a building permit. Structures considered "temporary" may not require permits. If there is no legal remedy, then you may have to plant something to hide it from view. Consider a trellis with a fast-growing vine.