Fence issue with neighbour and landlord

Ulfar

I may have missed it but the OP hasn't proved that this space is communal.

Rental contracts have nothing to do with it, the leaseholds do. It would be interesting to know what they say.

I owned a ground floor flat where the front and back yard where for my exclusive use except for a right of access for upstairs. The flat upstairs was bought by a landlord who rented the property out to a couple with a child. Not long after I get home to find my bedroom window broken by a football. The couple were very apologetic and paid for the repair, but I had to explain that the backyard was not theirs to use.

This may seem harsh but you don't want people right outside your windows. It does have an impact upon what you are doing.

The OP made unilateral changes that they may not have been entitled to make, I can see why the downstairs tenant was upset.

On a personal note the bamboo is unsightly. Also whose are the glasses on the meter cupboards.