Bear with me while I try to explain this for some extra advice/reassurance....
So, the party wall between us and our neighbours' is also the retaining wall for their property. The house and garden level is around 3m higher than our house as we are on a hill. The house has a lower level path along the party wall which is around 2m higher than our garden. We've discussed with our neighbours a 6ft fence on the party wall (it causes no damage to the structure as per PWA), given this is essentially floor height of the side path but lower than the house and garden level. The fence is around 10ft from our garden level now but 6ft from the path level. If we were to run it 6ft off the ground our side it wouldn't come to our neighbours ankles on their path. This fence gives both of us privacy as we were overlooked and we could also clearly see them too. They are so lovely, but of course everyone needs privacy.
Our neighbour is happy with the height, it doesn't obscure any view from the garden itself and if they walked to the boundary of their garden level, they could still see over to us, as this is higher than the path level the fence is on.
In the circumstances and off-setting the property heights due to the hill/retaining wall, we didn't seek planning permission and neighbour agrees to the work. The fence itself is at its highest, 6ft off the wall at the garden and steps down the side of the property gradually to 2ft on top of the wall.
I really hope this makes sense. I'm looking for some reassurance this is ok, and if there may be others in the same situation.
Thanks